My catfish are still in hiding but the Bluegill seem to be active all hours of the day.
Today I noticed they were bumping into one of the tubes leading to an air stone. At first I thought accidentally, but after observing them for a while it is apparent they are doing it own purpose.
They will get close, line up and then with a sudden burst of speed, ram the hose. They let it hit them close to the gill slits and drag the full length of their body. It's almost like they are scratching themselves.
They also hang out above the air stone. But they also swim to the bottom so they can approach the stone from the side. They will inch forward until the rising bubbles send them for a ride.
Is there any reason I should worry? At first I thought maybe they were not getting enough Oxygen, but now it seems that they are just passing the time.
If you notice that the scratching/flashing is excessive you might think about salting the system a little bit. If they are trying to scratch of ick then you might need to salt as high as 3 ppt but if it is just minor irritation then 1 ppt of salt can act as a general tonic.
Otherwise they may simply be board. Catfish do tend to be scardy cats and if there is food sinking to them you may rarely ever see them come to the surface if the bluegill are very aggressive but my catfish have learned to come to the surface to eat, heck they will practically come up and suck on the feeder.
I lost 2 more catfish today. Nitrates are still between 40 - 80 but 0 nitrites and ammonia. Ph 7.4-7.6 Water temp 76 f in the morning and 78 this evening.
They are moving around more now, but not like the bluegill. I see no discoloration or wounds on the fish.
Unlike the 1 bluegill I lost all the catfish have been retrieved after their demise from the bottom of the tank instead of floating.
I have 7 catfish and 5 bluegill in the same tank. I notice the bluegill go all over, but my catfish tend to stay at the bottom. They don't exactly do the behavior you mention, but i have seen the catfish try to find nooks and crannies by hanging around by my pump and the side of the tank. I put some smooth golf ball-sized rocks near the airstones so they wouldn't scratch themselves on the airstones. I noticed my catfish are more active at night so i feed them after dark. But i think the bluegill have caught on and feed with them now too.
I've lost 1 bluegill since starting about a month ago after cycling the system. It was floating. My water temps are now about 82-83 consistently with 0 ammonia and nitrites and 100+ nitrates. i need to add more plants. Ph is a bit high 7.8 but has slowly been coming down.
A thought that comes to mind is you may want to try feeding them something different.