Green sunfish too hot?

[firefly1152]

My sunfish are acting weird...
For the last hour or so, they're laying on the bottom of the tank mostly. When they swim, they let the current push them around.

I thought they might be too hot. The tank temp is 81*F. I don't have a cooler to put in there. I'm freezing a gallon jug of water but it won't be frozen for a while.

I do water changes every two weeks. Tank parameters are all normal.

Stocking : 75 gallon tank. Four 3 year old green sunfish. I have a 125 gallon ordered and waiting to be shipped.

Ammonia :0
Nitrite:0
Nitrate : 40-60 I always have a hard time telling.
Ph:7.8

Filtration is a forza fz13 and a wavemaker to increase surface agitation.

This morning when I fed them at 7am, they were begging, eating and acting normal. I started noticing them acting odd at noon. Does it look like they're heat stressed?

 

[kno4te]

Drop some ice cubes in there. It’ll help to cool it off. Turn off the lights. Get a fan.

 

[The Morning]

How oxygenated is the water?

 

[firefly1152]

Drop some ice cubes in there. It’ll help to cool it off. Turn off the lights. Get a fan.

I dropped 2 trays of ice cubes in there. They melted within a minute. So I did a water change of about 25% and filled up with cold water. Tank temp dropped to 75*, so at least it's a little cooler than 81 for now.

How oxygenated is the water?

Pretty well, I think. I have the spray bar pointed up and I have a wavemaker. None of the fish are gasping at the surface.