Oyster Reef Ecosystem Tank

[Subsea]

Kevin,
With warming weather, collection trips are in the que. Always glad to get updates on your systems.

My outside systems are ready for me to collect live food: green mollies, Ghost Shrimp and sheepshead minnows. I hope to do some of that this week.

[Chasmodes]

Yes Patrick, very true. I went collecting on Saturday. We had a great time and really caught some cool stuff. I've detailed below what we kept and brought below. More on that trip later in this post...it was a very cool trip and quite the learning experience.

I have some new additions to the oyster reef system in my holding tank shown in the video below. On Saturday, I brought home two small four spined sticklebacks, Apeltes quadracus, two species of Ulva macroalgae, a few more sea squirts and a cluster of mussels, and two beautiful large ghost anemones. When I say large, I mean about as big as they get, about 1.75" wide at the tentacles, and about the same length for the base. These are also not pure white like the others in my display tank. Rather, they have a pinkish hue to them. Here's the video:
https://www.youtube.com/watch?v=FZo3tRP58NQ

The sticklebacks are feeding on small copepods and amphipods, but ignore my offerings. I guess I'll have to start raising some baby brine shrimp or buy copepods until these fish are big enough to eat the frozen foods. My plan is to keep them in this tank for a while, but move them into quarantine and treat them with copper. At that point, the holding tank (my 20g high), will be for invertebrates and macroalgae, and will remain fallow. After 6 weeks, then I'll move stuff to the display tank. If I go collecting and bring more stuff home, then that clock resets. The point is that I don't want to introduce ich to my display tank.

Eventually, this summer, I hope, I'll have my big tank set up and all of the fish and invertebrates will move to that tank, except for the sticklebacks. I will keep the 20g long as a stickleback tank, with macroalgae as the dominant aquascape, with perhaps an oyster cultch or two (to be made later).

After this weekend, all of my fish that are in quarantine will move to the display tank. I had a tragic death on Friday night, however. One of the female blennies went carpet surfing. I have no idea how she got out. My guess is that she jumped through the egg crate top that I had, because there weren't any other openings large enough for her to fit though. Now I'm down to 5 males and one female blennies in the tank.

I posted this in the NANFA forum, but I'm not sure if I'm allowed to link it here. But, I'll just repeat the post here...this was my collecting trip on Saturday, 5/12/2018:

I took a friend (the aquarist at the Glen Echo Park Aquarium) out dipnetting to some sites on the Chesapeake Bay on Saturday. I wasn't expecting much because it seemed early to me. Last year, I didn't start collecting until mid-June, and although I caught my first blenny, it was a juvenile, and we only caught one. We didn't find any adults until about a month later. But what we found changed my opinion about the timing of collecting this ecosystem.

At our first spot, the SG was only 1.011 and the water temperature was 68F degrees. We caught the usual assortment of crabs, shrimp, a few mummichogs and three young four spined sticklebacks. I kept along with two species of Ulva, a few shrimp and some amphipods. We brought a ton of grass shrimp back to the public aquarium, as they make for great food for many of their larger fish. We collected a few naked gobies, but not many benthic fish at all at this spot.

All of my other spots in this region (considered "middle Bay") usually are within point of the specific gravity, but the second spot was actually 1.014, and our last spot was the same. We wound up catching quite a variety of species at these spots, including mummichogs, Atlantic silversides, rainwater killies, naked gobies, juvenile Atlantic croakers, one skilletfish, and two beautifully colored striped blennies. We also collected some invertebrates, including amphipods, shrimp, several anemones, a clump of mussels, some sea squirts, a couple jellyfish, and two species of mud crabs. But the cool thing was that we collected three species of benthic fish (two striped blennies, one skilletfish, and one naked goby) that were in oyster shells guarding eggs! We brought these male fish back to the public aquarium along with their eggs. When we returned to GEPA, the blennies were inside their oyster shells with the eggs. I thought that was amazing.

But, what I learned was the my preconception about it being too early to find blennies was all wrong. We found them in about 4' of water in discarded oyster shells with eggs, in May. I had much doubt that we'd find them this early, much less in spawning mode. It was quite a trip. Here are a couple pics:

Juvenile Atlantic croaker (these were released because they are well under the legal limit being a gamefish, and we didn't have our scientific collecting permit yet for this year- application in the works). These guys would have been great in their oyster reef exhibit. Hopefully, we will find them after we get our permit.


Male adult striped blenny, Chasmodes bosquianus, sporting his spawning coloration. We collected two of these guys, but no females collected this time. These colors were much prettier than this photo shows, especially the bright blue spot on the front of the dorsal fin that is really muted in the picture. We were so excited to catch these guys and that they were also both guarding eggs!

[Michael Hoaster]

Fascinating read! It's a pleasure following your progress. It's also very informative. Keep 'em coming!

[Chasmodes]

Thank you Michael! I brought home Ulva lactuca (same species you havce) and also Ulva intestinalis. It's very similar to lactuca but looks more like grass, as seen in the video. I really like the look of it. Plus, I found it attached to oyster shells!

[McPuff]

Very nice fish! You're a scientist? I assume that's how you can obtain a collection permit... I ask because I'm also a fisheries scientist. Well, I used to be anyway. :0)

[Chasmodes]

Thank you!

I'm not a scientist, but I'm helping with the local public aquarium, so they'll be listing my name on the permit to help them obtain specimens for their displays. For the vast majority of specimens, I can use my regular fishing license as long as I abide by the local game laws. The collection permit allows us to collect the species named on the permit and allow collection techniques that a fishing license doesn't allow (e.g. to collect undersized game specimens). I am pretty sure that I can't do this alone, that one of the aquarium officials has to be with me. At least, that is my understanding.

[Chasmodes]

The fallow period is over and my fish are not out of QT and back into the display tank. While in QT, they were pretty much doing the same territorial chases that they've always done, defending their favorite piece of PVC pipe. But, after a few days in the display tank, the males established homes in their favorite oyster shells and really colored up into their spawning colors, pretty much like the one that I caught last week. Not only that, they're defending their 6" of space, all the while chasing, flashing, and harassing the female, I guess, to breed. It's weird though, like a love-hate relationship. They get all fired up and flash when they see here, then they both display side by side and shake (mostly the male), then he chases her away. Only, all of the males are after her like this. Her tail has been pecked a lot, and at one point was almost down to the caudal peduncle, but has since grown back some.

The male spawning coloration includes a bright blue spot on the dorsal fin as well as a dark stripe and a yellowish/orange stripe along the front half of the fin. Also, they darken up their entire bodies almost to the point that their stripes fade away, their fins become tinted with orange, their pelvic and anal fins darken up and are trimmed with a white and black border, and their cheeks become and orange or peach color. You can really see this in the video that I'm posting below. That bright blue spot is quite pretty. The males are about 3.5 to 4 inches long now. In the six weeks that they were in QT, they grew quite a bit. It's hard to believe that it was less than a year ago that all of the fish were less than an inch and a half long.

The female remains in the juvenile coloration, mottled with vertical bars and faint horizontal variable stripes. She is the smallest fish in the tank at 2.75 inches, but she is tough as nails.

In this video, there are two scenes of a pair of males sparring over territory, presumably over a potential place to spawn and guard eggs. The first battle begins at the 3:30 mark, and the second one at the 5:02 mark. The video finishes showing the object of their affection, a female striped blenny.
https://www.youtube.com/watch?v=mac-arIZaXU

[Subsea]

Outstanding video of alpha male aggression between your collected blennies. The Ghost Shrimp population is large. They swim boldly in front of those blennies. Do they get eaten down fast? I have collected them in salt water marshes in Louisiana & Texas. When they come in with egg masses, it is neat to see the light thru the eggs.

Sounds like your collecting trip was spectacular. I always enjoyed collecting for my marine tanks. When the sport fishing was poor, I just as soon get out my dip net and catch things including pods and plants. If I would go to the jetties, I could get Peppermint Shrimp and Curly Que Anemone, that would be much better than fishing.

[Michael Hoaster]

Congrats on finishing fallow/QT time. Another fun vid too. I was surprised by your shrimps' boldness around the blennies. Quite the cast of characters!

I didn't see any of your new plants. How has your luck with plants been thus far? As I recall, you were planning to incorporate plants in your ecosystem, but I haven't seen many. Not that your scape isn't cool already!

If there is anything I can do to help on the plant front, please let me know. I'd be happy to help if I can.

[Chasmodes]

Thank you Patrick and Michael! When the fish were in QT, the shrimp swam much more openly around the tank. Now they are much less mobile, crawling on substrate more than swimming. The fish will chase them around now and then but lose interest fast. They have been known to kill and eat a few of them since the beginning, but these shrimp have all been in the tank since September. I think that as long as I keep the fish well fed, they'll pretty much leave them alone.

Our last collecting trip was much better than expected, with water temps just above 60F. They should be in the low to mid 70's by now, so collecting should be much better. As temps increase and the O2 saturation stratifies in the Bay, more fish will move shallow and thus improve collecting even more. I'm looking forward to adding more species.

The tank in the video has some of the black Gracilaria alive, but all of the Ulva died off while the fish were in QT. One reason was that I was trying to use less light to cause a die or or reduced level of cyano. Although it helped, it didn't get rid of it, so I will try the Chemi-clean. The lack of light pretty much killed the Ulva off.

In my 20g high, I added 2 species of Ulva, and already, the Ulva intestinalis (stringier Ulva) is dying off. The Ulva lactuca is still doing OK though. I don't know if the U. intestinalis prefers less salty water or not, or if something else is missing. I'm not too concerned yet since this is just a holding tank and my main big display isn't ready yet.

Since this tank has a couple fish in it, and it's my holding tank for inverts and macros, I won't be transferring anything into the display until this tank is fallow for 8 weeks. I have to transfer the sticklebacks to QT and then that process begins. For non-aquarium related issues, I had to break down the QT (I had planned to keep it up). I hope to remedy that situation.

Once the main display is set up, it will be my oyster reef tank. The 20g long will be the stickleback tank (maybe pipefish or seahorses), the 20g high will be the macro/invert fallow holding tank, and the other 20g long will be my fish QT tank. All those tanks plus my 75g FW river tank will provide me with much humidity in my house As far as progress goes on my large tank build, I had a water line installed to where I want my water changing/mixing station and my sump. Next is a dedicated electrical line. I also haven't finished the stand...feeling guilty about that...

[Chasmodes]

Tank update: I noticed that the fish in the 20g long were breathing heavily, mostly due to constantly defending their territories, but after a couple water changes to clean up detritus, I decided to also add an airstone. I also cleaned the HOB filter and powerhead and now there is much more flow. As a result, the fish are out much more and much more photogenic. While cleaning the filter, I discovered several tunicates in there, and also some inside some of the oyster shells. My original ones all died, so I assume that these are progeny. The three small anemones disappeared since I added the fish. I don't know if the fish killed and ate them, or if they simply moved or are hiding. In fact, all of the invertebrates except for the shrimp rarely come out (crabs, worms, etc.). Their vacation is over! Time for some pics...

Full Tank Shot


Male striped blennies battle over oysters and the lone female. The blenny that I dubbed "King" is on the left. He pretty much rules the roost but the one on the right holds his own and sometimes wins these battles

The next couple pictures show King sporting his spawning colors: the bright blue dorsal fin spot, the dark anal fins trimmed in black and white, the yellow/orange dorsal fin stripe, peach colored gills and mouth, and orange trimmed pectoral and tail fins. Notice how dark King gets in the above picture during the standoff.



The object of their affection, the lone female in the tank. Notice the drab coloration. She is quite a bit smaller too. The males chase her constantly, nipping at her, and sometimes shaking their bodies. I suggested to them that they take a nicer approach to courting, but it's hard for them to break bad habits.


King peeking out of his oyster shell that he defends constantly.


I have a couple more cool videos and will post them as soon as I can.

[Michael Hoaster]

Great pics Kevin! The third one is my favorite. It sounds like everything is humming along nicely!

[fabulousfavia]

Wow cool fish! What temp do u run this tank at?

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[McPuff]

Those are some cute fish. And great pics. Amazing how much difference cleaning the pumps/filters can make, isn't it? I intend this to be serious, not mean. :0) It always make me think, "I should do this more often."

[Chasmodes]

Thanks everyone! Michael, it's so tough to get a good picture as they never seem to stay still out in the open. I think that I might try getting a small mirror for them to show themselves off, that usually works.

Fabulousfavia, during the summer, this tank is about 68F degrees, and about 62F in the winter. Basically, room temperature in the downstairs of my house. In the wild, they live in shallow water in the summer where temperatures can reach 90F, and during the winter they head for deeper water where temps are as low as 40F during a cold winter.

McPuff, you are so right, and I was thinking the same thing. I regularly maintain my filter, but it's been a while with the powerhead. Not only did the circulation improve, the the pump runs a lot quieter... After cleaning them, I slapped myself on the head and thought..."Duh"...

[fabulousfavia]

Nice

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[Chasmodes]

My blennies spawned, probably on Friday. I didn't see the spawning activity, but was wondering why I wasn't seeing one of the largest males. The reason he wasn't out and about was because he was guarding eggs. He does make quick trips to come out to eat during feeding time, but goes back and forth between the oyster shell and the food.

Here's a pic of him guarding the eggs. You can see the eggs and also the female to the right hanging out. He is tolerant of her, but still chases her off if she hangs out too long.


Here is a pic of the shell and eggs that he left to chase off another fish:


Here is a cool video of him guarding the eggs. There is another male that challenges him, not for his eggs, but rather to defend another oyster shell that he is claiming as territory. This is interesting, because he is somewhat smaller and not even a week ago the two larger males were picking on him pretty bad. Now he fights back and stands up for himself. My guess is that he's claiming his own spawning location:
https://www.youtube.com/watch?v=9Qh8_B3pq4U&t=12s

[Michael Hoaster]

Congrats Kevin! You know you're doing something right when your fish spawn.

[Chasmodes]

Thanks Michael. Either that or these fish are so hardy that they can even withstand my husbandry!

In other news, after I reintroduced the fish from quarantine to the display, all of those cool invertebrates that were there that became more and more visible disappeared. I think that they are there, somewhere, but hide from the fish. I no longer have a cyanobacteria problem, so that is cool. The reef is looking more and more natural all of the time. The Gracilaria has died off some, but the pieces that remain are showing new growth.

Also, in my 20g high tank, I lost one stickleback. I have no idea what happened to it...gone. Maybe an anemone or crab ate it, or maybe it jumped out and I can't find it. The other stickleback is a pod eating machine and ingnores all of the food that I put into the tank. But, it's getting fatter, so my pod population must be sustainable for it. I think that once it ages, the diet will change. Right now, it's about an inch and a quarter long. The three anemones in that tank are doing very well, and all of the invertebrates in that tank are very active and out all of the time. Most of the macroalgae in this tank died off, but a big chunk of Ulva lactica is hanging in there. Most of the Gracilaria died off, but there are some small pieces that are coming back.

[Chasmodes]

So the female striped blenny is very brave, despite being smaller than all of the males. She struts about the tank and gets chased and harassed by all of the males. But, she keeps doing her thing. However, sometimes the chasing is more like corralling. Normally, a male will chase and bite her to scare her away, as he does rival males. However, when he wants to breed, he chase, nip, or sometimes push her to get her into his oyster shell, while at the same time positioning his body between her and the escape routes away from his shell, while shaking (flashing), with fins erect and displaying his colors to her. This is an attempt to push her into his oyster shell. I saw this happen a couple nights ago, and ran upstairs to get my phone. But, by the time I had it set on my tripod, another male blenny chased her off. He actually kept her from going near the other male, although probably not on purpose, rather, just to chase her away.

Meanwhile, another male on the other side of the tank had a different approach. He would just come out of his oyster shell and position himself higher on the reef above her, and kept doing that until she got close to his shell and eventually she would enter. He would follow her in and then she’d shoot out and swim away until this started all over again. He was so close! It was so fun to watch that I was down there from 10 PM until well after 1 AM watching this, trying to get a good video and/or pics. They never seem to behave the way you want when the camera is pointed at them.

Also, the territorial battles between the males and their shells is fun to watch in itself. Most of the time, the skirmishes are just all show. Sometimes, albeit rarely, they trade bites and even take chunks out of each other’s fins!

However, last night, I was able to capture some of this drama on film. Instead of one male doing this, three of them were competing for her! One of the males actually pushed her half way across the tank toward his shell, but she got away. I'm not sure if I got that on film or not. It's not in this video, but maybe I caught it in another one. I have to go through those videos to see if I can find if I caught it or not. Anyway, this is the best video of the action so far, especially the first third of the video. I can watch them for hours!

https://www.youtube.com/watch?v=4voYgaBffes&t=1s

[Michael Hoaster]

Spawning activity is so much fun to watch! It did look like one was trying to push her into his lair at one point.

Having one female to three males goes against the conventional wisdom of harems, but it seems to work fine in your tank. Not that all fish are harem spawners. Do you know of their social structure in the wild? Despite some mild aggression, no one is cowering in the corner, waiting for death, which happens a lot with other fish. Maybe the males' squabbling prevents the female from getting too much attention. There are many fish we are warned to not keep more than one male of, because they will fight to the death. Your males seem to tolerate each other pretty well!

Could this be the normal ratio for them? Maybe, in the murky world of oyster reefs, females are hard to find, so the males have to be more 'sensitive'. Whatever's going on seems to work well, and your fish are happy enough to spawn. And, it makes for fun vids!

[Chasmodes]

Thank you Michael! The ratio is probably more even in the wild. I had 5 males and 2 females until one went carpet surfing during QT. I will be doing a lot of collecting this summer (maybe not keeping, but sampling). I don't know if I can draw conclusions based on those samples or not, because I may not be collecting over ideal habitat (discarded shells vs. an actual oyster reef). But, from what I've learned from a scientist friend that I know that studies the genus, and also from the little bit of literature that I've found, that one male may spawn with many females, and the females may visit many more males at their oyster shells. Each female will lay eggs every two weeks or so in the wild, so I hope that happens in my tank. If I can add more females to the tank, this should take some of the pressure off of the one that I have. However, because this smaller version of my ecosystem is already crowded, I will wait until I get the big tank up and running to even up the ratio. That said, I may keep one female on a future collecting trip to ease things a bit.

What is interesting is how tough and brave these fish are. All but the largest of the males were relentlessly picked on almost their entire life by the largest male. Now they are all the same size except for one that is about a half inch smaller than the rest, and he is at the bottom of the pecking order. However, 3 other ones that were picked on their entire lives have really started standing their ground and fighting back, all in the last 3 weeks or so, once they established their territory. Each blenny seems to defend up to about 8" from their preferred shell. If their territories are closer together, that distance shrinks and, although some squabbles occur, for the most part, they tolerate each other. All that changes when a female gets between them (just like a movie drama)!

Also, in the wild, this genus establishes smaller territories and tolerate each other more than other combtooth blennies, as suitable empty oyster shells are at a premium. They tend to be in higher densities.

It's also interesting to watch the different ways that they encounter each other. It can be bluffing and displays, mild nipping, pushing matches or exchanging bites. One blenny may lose one battle, but might win the next, thus, each still able to defend their space.

I searched all of my unposted videos and don't have the encounter of when the male physically T-boned and pushed the female across the tank toward his shell. My guess is that if he did it once, he may do it again, and hopefully, my camera will catch it. I guess I need to set up a blenny cam!

[Michael Hoaster]

One of the takeaways I get from this, is that this hobby can be made easier if we chose sturdier fish to populate our aquariums. Thanks for reminding us!

[Chasmodes]

Indeed. Even despite me being the aquarist! My fish are almost bulletproof.

That said:

• I lost the smallest skilletfish the other day. It wasn't eating and shunned food. I didn't see any apparent disease symptoms. Even though it ate in the past, all of the other skilletfish grew to an expected adult size rather than this one. It's a mystery.
• My sticklebacks both disappeared without a trace. Both were eating pods like crazy and there seemed to be an endless supply of them. No fish carcass found around the outside of the tank or lid. My crabs and anemones seemed a bit extra fat and happy.

[Chasmodes]

I have some exciting news! After I got home from work, I went down to my tank to feed the fish and noticed that one of my skilletfish wouldn't leave his clam shell to come up and stick to the glass and beg for food. So, I shined a flashlight inside the shell, and when he moved away, I saw eggs on the upper shell half! He was guarding eggs and only feeding on food drifting by his shell. I made a point to plunge my hand into the tank in front of him with a pinch of frozen food, and he ate after a little bit of coaxing. It was weird because the other day, I only could find three skilletfish coming out for food, and I searched the tank high and low with a flashlight and couldn't find the fourth one. At that time, there were no eggs in any of the shells. So, apparently, the female skilletfish was the one that I couldn't find, and she was probably somewhere near the clam shell out of my view the entire time. I took a video of him guarding and fanning the eggs. I found it entertaining. Hope you all do as well.
https://www.youtube.com/watch?v=B4i3kLkCjIk&t=28s

Also, the gobies are acting differently, constantly flaring their fins and chasing each other, so my guess is that they will be next. The female blenny is about due to spawn again as well, as she is getting very plump.