Depressed Flowerhorn? Please help!

[Rubyblack]

I’m having some trouble with my Flowerhorn at the moment and I’m really worried about him. He isn’t eating much anymore and he’s very aggressive, whereas, he used to enjoy my company he now lunges at the glass when I go near him as if he’s angry. Throughout the day he sits at the bottom of the tank trying to hide behind anything he can. I do regular water changes and my water parameters are stable and normal, the advice I’ve gotten from my local pet-shops is that he’s just in a ‘mood’ or ‘phase’ and he’ll be back to normal in no time. But it’s been a few weeks now and I’m becoming increasingly concerned about him. If there’s anything that anyone could suggest I’ll try it, thank you

 

[The Morning]

What size is the tank and how big is the fish?

 

[Rubyblack]

What size is the tank and how big is the fish?

He’s about 20-25cm long and the tank is just more than 100 gallons

 

[Man-made Monsters]

Have you added any new lights in the room that the tank is is??? Like desk lamps, over head lighting, or fans?

 

[islandguy11]

That he's getting more aggressive and protective of his domain isn't really something to worry about, in fact it's quite natural for most FH. But decreased appetite and hiding all day are concerns, esp. if going on for several weeks.

Along the lines of Man-made Monsters' inquiry, are you sure there haven't been any environmental changes, internal or external?

If not then I would start to think along the lines of possible internal parasites -- is your FH local or imported from Asia, and have you ever de-wormed him? (e.g. with something like praziquantel) FH's are usually voracious eaters; when that changes it could likely indicate some current or impending health issue.

Btw, just to cover all the bases I would also check to see if you might have too much stray voltage in your tank (maybe not, but it's worth checking).

 

[Rubyblack]

Have you added any new lights in the room that the tank is is??? Like desk lamps, over head lighting, or fans?

Nothing new, I’ve actually started leaving most lights off surrounding his tank and only turning them on few about an hour at a time just a few times a day. I’ve found that he’s more active with the lights out but still not as much as he used to be.

 

[Rubyblack]

That he's getting more aggressive and protective of his domain isn't really something to worry about, in fact it's quite natural for most FH. But decreased appetite and hiding all day are concerns, esp. if going on for several weeks.

Along the lines of Man-made Monsters' inquiry, are you sure there haven't been any environmental changes, internal or external?

If not then I would start to think along the lines of possible internal parasites -- is your FH local or imported from Asia, and have you ever de-wormed him? (e.g. with something like praziquantel) FH's are usually voracious eaters; when that changes it could likely indicate some current or impending health issue.

Btw, just to cover all the bases I would also check to see if you might have too much stray voltage in your tank (maybe not, but it's worth checking).

Thank you for the advice, I’ve arranged to get some worming treatment just to be safe but I’ve had multiple fish gurus take a look at him and the tank and they haven’t found any parasites. He was local not imported. I take my water down weekly for testing but everything seems fine according to the tests, there hasn’t been any external changes and nothing internal found either. I’ve been advised to buy him more ornaments to amuse him but previous attempts haven’t worked and I don’t want to disturb him further. I think that if he’s doesn’t show any signs of getting better after the worming treatment I will pass him onto my local aquarium store, they says they’ll try to help him and possibly rehome him if he needs a larger tank. Thank you for your advice