Please help my Flowerhorn which is lying to it's side at the bottom of the tank

[Avanika_54]

Was there any strange behavior before this, or he was fine and then suddenly on his side?
What is your water change schedule, what size tank is that, what are your nitrate nitrite ammonia readings? If you don't have a test kit, you can bring the water to most fish stores for a test ,although some like petsmart may not give you accurate readings, better to have your own kit.
It does look like a bulky fish in a small tank, possible that water conditions are poor unless there are lots of water changes being done.
Flowerhorns are also inbred and often have birth defects which can pop up even later in life, could be a combination of factors.
It's hard to give advice with the information we have now, but if you answer the questions above it will be easier to tell what went wrong.

No strange behavior before this every 15 days i change water but i was late to change it and the strange behavior started
it has been 1 week since this happen and it didn't eat any food water now is in peak condition only half tank of water is kept in dim light
I added espom salt
Now condition is severe

 

[Randles]

Personally I'd put him out of his misery with clove oil. Poor thing! This is now the only humate thing to do in my eyes and I hate giving up on any fish, but I think I would in this case. I know you say he was in excellent condition but water changes every 15 days isn't going to cut it. Ending his suffering would be my priority. Sorry.

 

[jjohnwm]

Agree. Sorry to see this happen to that fish. And must tell you that with water changes every two weeks (especially when you mention that your last one was late even according to that leisurely schedule) the water quality in that tiny tank with that size of fish simply cannot be anywhere near "peak condition".

 

[Gourami Swami]

No strange behavior before this every 15 days i change water but i was late to change it and the strange behavior started
it has been 1 week since this happen and it didn't eat any food water now is in peak condition only half tank of water is kept in dim light
I added espom salt
Now condition is severe

Should be changing water at least 1x per 7 days, goal is to keep nitrates low, which you should be testing for with a kit. I keep mine under 20ppm, usually lower. Thats a pretty bulky fish in not much water with not enough cleaning, im guessing water condition was the cause though I can't be sure. But now you know for the future.