[eschaton]

In my old tank (setting up another one soonish) I didn't have a formal lid. I did however put diffuser grate over the surface, with some small cut-out areas around the downspouts and a handful of other pieces of equipment. Even with these relatively small openings, I still lost a fair amount of fish to jumping, including a Yellow Watchman Goby, A Yasha Hasy Goby, a mandarin, and eventually my Sixline Wrasse (though he lived happily in the tank for a good five years before he jumped). Indeed I never had an issue with fish illness - I basically only lost fish due to jumping, barring those rando fish that vanish as soon as you put them in the tank, and some small gobies that likely died of old age.

When I look at modern setups online, it seems like lidless has become the default. From an aesthetic standpoint I can get behind this. The newer LED fixtures are small and don't need to have bulky ventilation systems, meaning a lot more of the water surface can be exposed.

However, I have always heard that when it comes to saltwater fish, basically all of them - with the possible exception of seahorses - will eventually jump if kept in a lidless tank for enough time. Meaning if you care about the welfare of your fish, the only real solution is either to have a lid, or a coral/invert only tank.

Which makes me wonder if all of these lidless setups are just for show.

Anyway, thoughts?