Just moved - almost lost a fish

I just moved my fish to a new home. They went from a 55 gallon tank with a powerhead-driven sponge filter to a 75 gallon with the old 55 as a sump, now with lava rock as filter media.

The new tank has 50 pounds of Special Kitty litter to grow plants. The 5 days they spent in a 5 gallon bucket seems to have removed the algae that was clinging to them before, and I think I've eliminated the trumpet snails in favor of native ramshorns.

When I added the fish I just dumped them from a 5 gallon bucket, thinking that would be the least stressful. They were still understandably spooked, and immediately dove for cover including trying to swim into the substrate. One unfortunate bluespotted sunfish succeeded. The particles of kitty litter are evidently light and loose-packing enough when new that he was able to burrow in. It took me almost a full minute to find him - only the tip of his tail was visible. I dug him out, and he just kind of sat there, breathing hard, with mud stuck all over in his slime coat. I'm sure he would have died if I hadn't pulled him out.

They were still understandably spooked, and immediately dove for cover including trying to swim into the substrate. One unfortunate bluespotted sunfish succeeded. The particles of kitty litter are evidently light and loose-packing enough when new that he was able to burrow in. It took me almost a full minute to find him - only the tip of his tail was visible. I dug him out, and he just kind of sat there, breathing hard, with mud stuck all over in his slime coat. I'm sure he would have died if I hadn't pulled him out.

*headdesk*
Here, take a look at this photo: http://gallery.nanfa...hiding.jpg.html

Yeah, that's happened to my Elassoma gilberti, too. Poor fish. I now pack the kitty litter down with my hands as soon as there's an inch of water in the tank. Then I continue filling the tank, slowly. If you pour water directly on the kitty litter, it's extremely dusty. I use a Python faucet connection to fill the tank without disturbing the hard packed, yet dusty and fragmentable, substrate.

You have to pack the kitty litter down with your hands to condense it. It can be loose or dense, depending on whether or not you pack it. If you pack it together, it can be like a rock. If you pack it, the fish won't be able to burrow into it.

Edited by EricaWieser, 17 January 2012 - 12:17 AM.

I never had a fish burrow into sediment in a tank but I have seen it while sampling once. Small pointy looking brownish fry burrowing when I go to scoop them. I never did catch one and still wonder what they are. I almost wonder if darter fry burrow to excape threats.

I would suspect that the fish are simply trying to find rock crevices, or partly exposed root system, to prevent predators from getting access to them. After failing to find an effective crevice or well enclosed hiding place they resort to digging under mud or gravel as necessarily and to the best of their ability. I suspect this digging behavior would stop if they had more readily available and tight hiding placed. Crevices small enough to exclude anything bigger than it is.

Just my guess.

I would suspect that the fish are simply trying to find rock crevices, or partly exposed root system, to prevent predators from getting access to them.

Oh, that makes sense. In my experience when you go to catch a fish with a net they always swim down. If you come up underneath it with the net they don't see it until the last moment and even then swim down into it. Catching fish can be really difficult if you come at them with the net from the side or above.