[Brothermist]

Fish in this tank are:
12 White clouds
8 long fin Zebra Danios
1 Male Guppy (a rescue)
1 Neon Tetra (sole survivor of Neon Tetra Disease that claimed all others)
5 SAE's
4 Otto's
18 Adult False Julii corys (started with 8)
??? lord only knows how many baby/juvenile False Julii's

BDBS substrate (tank has been going for a few years with this substrate, no injury to Corys)
Root tabs & Thrive +
2x Finnex Planted + 24/7 CRV's
2x Sunsun 704B's (yes, overkill I know)
C02 injected via 5lb w/ custom 2 stage
RODI setup remin'd with SaltyShrimp GH/KH+

Tank has been running this set-up for quite a while now and both fish and plants seem quite happy.

Fair amount of random plants, stem plants recovering from being without c02 for about a month. >.<'

Anyway...
My 40B did not have a lid on it until about 2 weeks ago. Until then I only ever had 1 cory jump to its death.

2 weeks ago I had a SAE that launched itself out of the tank onto the concrete floor, a four foot drop. Luckily I was right there when it happened. Picked him up, cleaned him up, returned to tank. He was stunned for a while, just hiding in one spot. After a while he just started swimming around eating again. Same day one of the Corys almost did the same thing.

Well, that day I went to my local pet store and got a lid. I had to mod the tank to get it to fit, but its on.

Fast forward to today.
I'm sitting at the tank just enjoying it and I hear a loud thunk, followed by one of the older juvenile corys now frantically swimming in circles against the back glass...inverted. He slowly calmed down and settled on the bottom, still upside-down. 5 mins later he's still updide-down, slowly moving into the plants where he disapeared.

I've heard the random Cory bump into the glass here and there since I put it on, and on occasion one of the SAE's will really smack into it.
Is there a cover/lid I can change to that will not block too much light, yet be a little easier on my daredevil fish?

Oh, that SAE that jumped out and slammed onto the concrete floor... 2 weeks later he's fine. Tough 'little' booger. ( he's not little )

Thanks for any help.

 

[Aaronious]

how close to the surface is this top? Do you add have an air line? if not do you have good surface agitation?

My corys tend to shoot up every so often, pleco too. SAEs not so much and the others only once in a while. My first thought is maybe they want more air?

 

[ichthyogeek]

It sounds like you have an all glass or all plastic lid. The lids I'm more familiar with have a frame, and are made of a soft mesh (as opposed to metal mesh which is hard).

Another option might be to lower the water level just a bit. If your lid is right next to the water surface (1" or less), then giving some room for the fish to dart up and grab some air would be a good idea.

Finally, do you know what's causing hte fish to jump? How's the water they're in parameter wise (nitrogen waste, temperature)?

 

[Plinkploop]

I was going to ask about parameters as I've kept mostly open top tanks and have only really had issues with true jumping out when there's nitrite in them (or other chemical contaminant) or when there's not enough oxygen. Other than that they barely breach the surface when they dart to the surface. This is just from my own experience, I know plenty of people that have issues keeping sae contained without a cover.

 

[Sequoia Exotics]

Yeah, corydoras come up for air pretty often, but usually when they have some sort of oxygen deficiency. I would consider testing your water and getting a small airstone. As for the lid, you can get clear, plastic sheets (sometimes called corrugated plastic) at most home-improvement stores. These can easily be cut with scissors or a razor blade to fit any tank and should be a bit softer on you corydoras if they continue jumping.