What would be the perfect size tank for my fh?

[tiroloco]

I was wondering what size would be ideal to fatten my flowerhorn up, i had it an a 60 gallon tank and once it started growing i switched it over to a 180 thinking it would be happier with the extra space, but ever since the switch it has lost weight and it isnt eating like it use to

Currently the flowerhorn is about 5 inches long

 

[Brian_Indiana]

I have mine in a 90 alone. http://www.monsterfishkeepers.com/forums/album.php?albumid=4537

 

[hamfist]

I was wondering what size would be ideal to fatten my flowerhorn up, i had it an a 60 gallon tank and once it started growing i switched it over to a 180 thinking it would be happier with the extra space, but ever since the switch it has lost weight and it isnt eating like it use to

Currently the flowerhorn is about 5 inches long

That's a bit odd. I would expect any cichlid to enjoy extra space. Maybe your fish is slightly nervous and the new, bigger, tank doesn't have quite as much cover for him/her.
Maybe the 180 had some infection that the FH has picked up ?

Maybe the Fh just needs time to settle in ...... although in my experience most well-adjusted FH's take no more than 24-48 hours to settle in a new tank (if not much quicker).

My own personal experience on a similar theme is that I recently moved my 9" ZZ RD from an 80G to a 150G (all on his own). He's loving the extra space.