
I have a problem I noticed today. 3 to 4 of my 8 fancy gold fish have started rubbing them selves on the pebbles just before they rub them self they swim a little bit fast. It stops & they don't do it again for long periods of time. There are no other signs that stand out.
Their are 8 of them in a 200L tank with an excellent rena external filter. I know there should be only 4 fish in 200L they are still small & have plenty room, but will divide them in to two groups of 4 at some point.
I feed them once daily with a mix of the usual ive food & pellets, & fast them once a week also.
I used to do x2 50% water a week & once a week use the the gravel cleaner.
Now I do x1 50% water change a week, gravel clean x1 week to. They have live plants only.
I've tested water every thing was fine how ever I did just do a 60% water change & of course treated water before hand.
Can anyone tell me what the problem could be? & suggest what I could do?
Thanks in advance