Angel Fish On Side

[55gal]

For the last three days every morning my angel fish is up by where the water from the filter comes out into the water and is on his side. I turn on the light and turn up the filter (I turn it down before bed) but the filter water hits him and pushes him around so I keep it down until he rights himself which takes a few minutes. He is fine but sticks to on corner of the tank (which he has done since my other angel died, the bleeding heart tetras stay there too, it's right under the filter, behind a fake plant). Right before I go to bed he is starting to swim crooked again. He is not completely on his side but is half way there. As soon as I turn the filter down he rights himself, much faster than in the morning. This morning a guppy was dead. What do you think is wrong with the angel and/or tank?

 

[england]

ah i see angels......when the light of they doe this strange angle of swimming........how long have you had them and tank running?
i would guess the guppy has died because you keep turning of filter....

 

[55gal]

It's been a little under a year Since the tank started running...the guppy has been alive longer than a year though. The angel was one of the first fish we got in the tank.

 

[WILDER]

Water stats would be good in ammonia,nitrite,nitrate, and ph.
Is the spine bent.
Has the angel gone thin or bloated up.
Check the anus of the fish to see if its enlarged or red and inflamed.
What does it look like when the fish goes to the toilet.