problem with tank/fish ?

[batang_mcdo]

Hi Need opinion regarding fish in my tank. This are feeder fish, they have been born in my Arowana's tank, and have grown since my arowana decided he doesn't want to eat feeders anymore

I noticed thta there are some whitish growth on the feeders? what could be the cause of these? or are they normal markings?

My arowana tannk has been running for more than a year already.
temperature should be about 26 - 28 Deg celcius since this is an indoor tank.

I'm just curious about the whitish color on these feeders?
they do act healthy though.

I'm a little worried since there was some problem with my arowana before

but after water change the symptom is gone in my arowana.
symptom has been gone for a while in my arowana though.

 

[MonsterMinis]

I've never seen HLLE on an arrowana before? i'm assumeing that what it was? if thats the case i would surmise your issue is high nitrates.. or possibly ammonia burn on the feeders? i would test your water quality. it is also possible the feeder is developing fungal infections, but these are pretty rare.. usually it's bacterial related to poor water quality.