How common is infection of bluegill in a 150 gal tank?

[Griffin Fowler]

I have 15 bluegill and a 1 foot long catfish in a 150 gallon enclosure. I was wondering if it is likely they will get sick or infected and if they do how do I stop/prevent it?

[C Barb]

I have 2 tanks with cichlids, bluegill and other sunfish. One is a 135 gal and the other is 75 gallon. I took everything out of the 135 to build a 3d background and placed them all together in the 75 and within a week the tank got sick.  The cichlids got ick then they all got cloud eye disease. Never figured out what caused it. Both of the tanks were healthy seemed to me before joining the fish together in 1 tank. I treated the tank for ick and parisites several times with the active carbon removed and did atleast a 20% water change daily. By the time I got it under control I had lost about 60% of the fish. The fish that are left (1 greenie,5 bluegill, couple cats)seem to be doing well.

[Bassandgrass]

Remember is since it's a closed system any sudden changes will stress the fish. In any aquarium nitrates will naturally build up. The nitrates themselves aren't really toxic to the fish but at high levels they will stress the fish and weaken their immunities, making them more likely to get sick. To combat high nitrates do partial water changes with a gravel vacuum in order to remove as much waste as possible. When refilling try to match water temperature as close as you can, a couple degrees is fine but too much of a sudden water temp change also can stress fish and weaken resistance to sickness. Another thing is to add water conditioner to remove chlorine etc from tap water. just my $.02 hope it helps