We've got a new 125 gal tank that is cycling up. It has had 4 young silver dollars in it for 8 days now. As of last night, the ammonia, nitrate, and nitrite are all low or at zero. PH is at a solid 7 or 7.1. I believe that the tank already had an ammonia spike earlier in the week (using a test strip). However my "real" test kit confirmed last night that everything his died back down to zero.
I've got 2 big silver dollars (started out as the same size as the little ones, I've just had them for a year) in another tank. The plan is to move them into the 125 since their current tank is getting a little too small for them.
My question is, is it safe to move the big fish to the 125 yet? Has it properly cycled? Or are the 4 smaller fish so small for such a large tank that they aren't having much effect on the nitrogen cycle?
Aside from cycling issues, is there anything I should be aware of regarding introducing 2 large silver dollars into a tank with 4 little silver dollars already in it?
And on a side note, how soon can I add a black ghost knife fish? Thanks!