Oyster Reef Ecosystem Tank

[Michael Hoaster]

Looks like all is well! The oysterscape looks and works great. Cool what all you're learning from your local biotope!

[Chasmodes]

Thank you Michael!

I was thinking about the health of my tank last night. My fish seem to thrive even though it's a small tank. I have 11 fish that are between 3 and 5" long. They're all fat and breeding. When I caught all my fish, they averaged and inch long, and grew to adult size in about 8 months. I've had this tank set up for two years now. I began with 7 striped blennies, 5 skilletfish, and 5 naked gobies. I now have 4 striped blennies, 2 skilletfish, and 4 naked gobies.

How I lost fish:
Blennies - One adult female blenny jumped out of the tank after my disease outbreak while being treated in QT. The other blenny lost was a male that jumped out of my DT a couple weeks ago. I had one adult male blenny die after going blind about 6 months ago.

Skilletfish - Two adults died of disease during the outbreak, one just went missing this week (it was the one that wasn't eating). I assume it was an internal parasite.

Naked gobies - I lost one a few months ago, unknown, found dead but seemed healthy until then.

I haven't been testing my parameters in months. I got lazy, so last night, I tested for ammonia (zero), nitrite (zero), nitrate (50). I thought that if a fish was missing and died, that the levels would have been elevated, but not, so I was surprised by that.

Invertebrates in both tanks:
Ghost anemones - I had three in my DT and thrived until I returned my fish from QT, then they disappeared. I had three in my invert tank, and one is huge and thriving. The others could be alive somewhere in the oyster cultch. They move around a lot and are hard to see, but I haven't seen them in a month or so.

Tunicates - I had them in both tanks. They live about 6 months as adults then die off. Every now and then, I'll find one inside an oyster shell, but haven't seen any in a while now (about three months). There could be some deep in the cultches, but I may have killed them when I pulled the reef apart for repair, because the reef was dry for a few days.

Barnacles - Some died that I collected, but, I still have a few (2 different species) that have lived for over a year now and are doing well. I think that once they survive the early stages of captivity, some adapt and do well if fed properly.

Mussels - Same as barnacles, I've collected and kept about a dozen of them between the two tanks, but most have died off. I still have four alive that seem to be doing well that are a year old now.

Grass Shrimp - I've been able to keep them in the DT with the fish for about 6 months, then they gradually disappear. Some jump out of the tank, and I think the fish killed and ate some too. In my invert tank, they can't get out, and have lived over a year now. I started with about 30, and there are about 20 left, but, they're hard to count because they move around a lot, and hide throughout the reef. So, there could still be 30 in there.

Mud Crabs - I've kept two different species. In my DT, I didn't find any when I pulled out the reef, but, there could still be some in the tank. They hide in the reef and also bury themselves, and I really didn't look for them. Some may have died or crawled away when I pulled the reef out of the tank. I haven't found any on the floor though. In my invert tank, there are 6 mud crabs, at least, that I see now and then.

Bristle worms - They are doing well in both tanks. I see them out all the time in my invert tank, but never come out in the fish tank. I see them burrowing around the glass in the sand though, so they're there. I think that they only come out at night.

Amphipods - The fish ate all of them in the DT, but some are still alive in my invert tank. I see them now and then feeding on algae on the glass. They're nocturnal, and very wary, and hide all the time.

Copepods - I had a bunch that I always saw on the glass, but since I used Prazipro, I haven't seen any lately. It might be because I cleaned the glass, but I used to see a few even then. The glass is starting to get algae again, and is due a cleaning, but I think I'll wait and see if any pods appear. I never see any in the invert tank, because I think that the anemones eat them. I'm sure that some are living in there though.

Snails - I found one lone micro sized snail living in my DT when my fish were in QT. But, I haven't seen it since the fish were returned. The fish may have eaten it.

One possible thing that could have happened is that maybe some of the inverts that died off in my DT when I returned my fish from QT, could have been due to elevated ammonia. I did water changes during that time and tested, and there was some ammonia and nitrite present, prior to the water changes. That could have caused the die off rather than the fish eating them. I don't think it would have affected the grass shrimp, but the anemones and snail could have been victims due to that.

So, the question, in my mind, is, will some of these inverts survive with adult fish or are the fish killing them? Ultimately, I'd like to keep the whole cast of characters, a true biotope. We will see.

[Michael Hoaster]

Ooh, that's a great thought process! Going through an inventory of livestock over time, and speculating on what helped or hurt them, is a smart idea. Predation and starvation are two huge factors, especially in the confines of an aquarium.

Then we have to decide on our priorities. Is one particular fish more important than pods or worms. Is it worth it to keep certain inverts that require phytoplankton feeding, etc. It's a lot of choices.

We all have different puzzles to solve!

[Chasmodes]

Originally Posted by Michael Hoaster

Ooh, that's a great thought process! Going through an inventory of livestock over time, and speculating on what helped or hurt them, is a smart idea. Predation and starvation are two huge factors, especially in the confines of an aquarium.

Then we have to decide on our priorities. Is one particular fish more important than pods or worms. Is it worth it to keep certain inverts that require phytoplankton feeding, etc. It's a lot of choices.

We all have different puzzles to solve!

Exactly! Thank you Michael.

I have flexibility with replacement critters because I can collect my own livestock and replace as needed to keep the up the full biotope, as long as it's warm enough to collect. And, it saves me money. Plus, if any winds up as food, it's natural to their regular environment and good for them.

The fish are the main players in my tank, for sure. But, I also would like to have the natural process run my tank as much as I can. That's why I'd like to see how the snails and fish interact in a tank together, so I can complete the clean up crew. The mud crabs and grass shrimp do a pretty good job, as do the bristle worms. I'm pretty happy overall with compatibility. I haven't observed that much predation (a little), so we will see.

Fortunately, if I can get macros to grow long term, or better yet, eelgrass, then I know that my current fish won't dig them up much or eat them. It may affect what newly collected fish make it into my DT though from that point on. It's all good though!

By the way, the anemone, for a ghost anemone, is a beast. I feed it one small shrimp (bigger than mysis, more like a small popcorn shrimp at KFC without the breading) about every three days. I'll have to take a video of it. I know that watching an anemone eat is like watching paint dry, so I'll make sure to keep it short, LOL.

[Michael Hoaster]

Good point. Collecting locally allows you the luxury of replacing lost critters. I guess we all can replace stuff as well, though it's tough to swallow paying again and again, not that operating a boat is cheap!

I've noticed that both of my new damsels hunt benthic critters, even though they are water column plankton pickers. I hadn't planned for this. I expected that pod populations would grow and grow. Now I'm not so sure. I may be forced to consider the monthly pod deliveries I've seen available lately.

[Chasmodes]

Originally Posted by Michael Hoaster

I've noticed that both of my new damsels hunt benthic critters, even though they are water column plankton pickers. I hadn't planned for this. I expected that pod populations would grow and grow. Now I'm not so sure. I may be forced to consider the monthly pod deliveries I've seen available lately.

They are creatures of opportunity with the ability to adapt as life requires. In the wild, there's a seemingly infinite supply of floating plankton, where the need to hit the bottom isn't normally their style. Have you considered culturing your own pods? I guess you might need to culture phytoplankton too, but at least you'd have a good supply of macroalgae (especially Ulva).

[Michael Hoaster]

Very good point, Kevin. Its just in my experience, plankton pickers don't touch any food once it touches the ground.

I'd like pods to flourish right in my tank. With increased predation, I'll have to make my in-tank refugium more accommodating. I've got some Ulva growing in there. I'll add more.

[Chasmodes]

Originally Posted by Michael Hoaster

With increased predation, I'll have to make my in-tank refugium more accommodating. I've got some Ulva growing in there. I'll add more.

Sounds like a good solution to me.

[McPuff]

Originally Posted by Michael Hoaster

Good point. Collecting locally allows you the luxury of replacing lost critters. I guess we all can replace stuff as well, though it's tough to swallow paying again and again, not that operating a boat is cheap!

I've noticed that both of my new damsels hunt benthic critters, even though they are water column plankton pickers. I hadn't planned for this. I expected that pod populations would grow and grow. Now I'm not so sure. I may be forced to consider the monthly pod deliveries I've seen available lately.

Damsels don't really follow any rules. They are the epitome of opportunistic fish. A generalist through and through. Perhaps that's one reason they are so fun to have in a system. Now that I've added a few more (total 5) I will probably add 4-6 more. :0)

[Chasmodes]

If I can ever find any tropical strays up my way, I'd add them too!

[Chasmodes]

Recently, I posted the status of life in my tank, and pointed out that anemones disappeared from the 20g long fish tank, and that I hadn't seen two anemones of the three that I knew were in there in a long time, and thought that they were dead in the 20g high invert tank.

Well, I have an update. In the 20g high invert tank, I found one of the anemones. It must have been hiding in the oyster reef, and finally moved out into the open one day. Here is is, stuck to one of the oyster shells.


Then, two nights ago, I pulled out my magnifying glass and was going around the tank looking for other life, and found an anemone! All this time, I thought that the anemones were killed by the fish in this tank. It was poking out of the sand, tentacles only. At first, I thought that they were worms, but under closer inspection, definitely an anemone. It hasn't been out since then, unless it moved again. I don't have a picture of that one yet. I have to wonder about the other anemone that was in there, if it's still alive too.

Anyway, I thought that was pretty cool.

[Michael Hoaster]

That's good to hear. Maybe they lay low in the coldest months. Hurray for magnifying glasses! They're such useful tools, in our miniature worlds. Great for spotting small problems, before they become bigger ones, and great for finding little rays of hope among the messiness.

[Chasmodes]

I'm am always fascinated by my view through the magnifying glass of my tank. I'll go down with the intent of feeding them and watching them for a short while, and I always stay an hour past my intended time, resulting in a lack of sleep sometimes. I seem to find something different each time. There are still jellyfish larva in my tank too. They bud off tiny medusae often. I think that they eventually get sucked into the filter. But, the polyps show up often too. I think that I killed some of them during the reef repair, but I"m sure that some of them lived, because I saw a tiny medusa floating the other day. I'll try and add more diversity this year by gathering some mud and sand on my collecting trips. My main concern about that is accidentally adding harmful isopods to the tank.

[Chasmodes]

Well, I was wrong about another thing about my tank. The "missing" skilletfish that I hadn't seen in a week, was on the glass near the other two skilletfish that were waiting patiently for me to feed them. This particular skilletfish wasn't interested in any of the food that I dropped into the tank. It's as if it couldn't see the food. Yet, it looked fat and healthy. I don't get it. It must be eating. Maybe bristleworms? Anyway, I'm relieved that it's still alive and seemingly well, but concerned about it shunning the food that I drop in. Maybe it eats leftovers off the bottom later.

Also, I hadn't see any jellyfish polyps since I broke down the tank, until this morning. I went down, before my tank light comes on, and shined a flashlight along the bottom to see if I could find the anemone, and lo and behold, on the sand bed nearby, were a colony of jellyfish polyps. I scanned a bit to the left, not far from where the anemone was, and saw tentacles. More anemones? Or, was this the same one that moved? Weird. Just plain weird, but cool, at the same time. I'll try and get a picture.

[Michael Hoaster]

All is well then! I look forward to hearing what you collect this year.

I think your progress is being limited by your small tanks. Maybe you'll be inspired to get the 101 up and running?

[Chasmodes]

Originally Posted by Michael Hoaster

I think your progress is being limited by your small tanks. Maybe you'll be inspired to get the 101 up and running?

Agreed. My goal is to have it up and running, and cycled, so I can add to the collection this summer. I'm not sure that I'll have the sump plumbed in this summer, maybe. I have a lot of work to do with my infrastructure to make that happen.

[Michael Hoaster]

Sounds good. I'm excited for you!

[Chasmodes]

I took a close up video last night of the blenny eggs. They're probably going to hatch soon. If you look closely in the video, you can see the eyes in each egg, at least the ones toward the front of the oyster shell. I also like when the blenny returns to tend the eggs and hang out of the oyster shell. You can really see the detail in the coloration and structure of his head.

https://www.youtube.com/watch?v=enxxmx3-1Ck&t=9s

[Michael Hoaster]

I could see the eyes! It must be nice, having fish happy enough to spawn. Props!

[Chasmodes]

While searching for the anemone that I saw a few days ago, I found more anemones. There are three small ones, as it turns out. The first anemone must be buried. In an earlier post, I thought that the blennies killed off the ghost anemones, but, apparently, the original two not only survived, but have reproduced. I find that fascinating.

I took a video. The first half of the video shows the three small anemones. Then, I pan right to the jellyfish polyp colony. I have since found another jellyfish polyp colony to the right of those.

Again, I quote Ian Malcolm (of Jurassic Park) - "Life uh...finds a way..."

https://www.youtube.com/watch?v=lgk6Bd3bp4A

[Michael Hoaster]

Cool. Good music choice too. It went well with the subject!

That phrase does get tossed around, I think because it is so appropriate! We put Nature in a box and it goes right to work. I'm astounded how well it adapts to whatever we throw at it.

"Now you will remember to wash your hands before you eat anything."

[Chasmodes]

Originally Posted by Michael Hoaster

"Now you will remember to wash your hands before you eat anything."

Ha! That is so appropriate too, especially after we feed our fish or work on our tanks!

Edit: I meant to also say that quote also cracked me up in the context of that movie!

[Chasmodes]

This morning, I went down with my flashlight and magnifying glass to see what was active before the lights were on, looking for that first anemone. I found it, plus the three in the video...but...there are actually four in the video! And, I found another one on the other side of the tank, making it 6 anemones! Man oh man, have they ever reproduced!

[Chasmodes]

Everyone's probably sick of my tank by now with all of my updates, but, I can't help it. I love it and want to share it LOL.

The skilletfish that disappeared and then reappeared died. I found the half eaten carcass floating at the surface. The blennies and other skilletfish looked pretty fat! They still ate like pigs when I fed them. When it was alive, it had no signs of disease. I just stopped eating.

Here's a video update. The fish were a bit skittish this time, not sure why.
https://www.youtube.com/watch?v=atLsEOccI8I

[Michael Hoaster]

I liked the full tank view you started with. It gives you a sense of the scale. Then it was fun watching them play 'musical chairs' with the shells.

Sorry to hear you lost one. It may be Nature's way of getting you to the best number of fish for your tank.

This is something I'm mulling over with my plan of multiple damsels. They are pretty cool when they are juveniles, but get meaner and more territorial as they age. So it's difficult to know how many fish is ideal, because that number goes down as they age.