I am fairly new to fish keeping. I acquired a free 15g fish tank, no leaks, great condition, with some healthy and established bacteria in the substrate. I have 4 Cherry Barbs (1 male, 3 females) currently in it since 03/09/19 (Saturday). The pH level is fine; the temperature is 75F. My filter is new (AquaClear 30). This is my first set up, and I would like to be successful, helping my fish to grow.

I am wondering about things to watch for in a fish-in-the-tank cycling process; I know it is possibly more difficult than a fishless cycle, but I have already got the fish in it. I am thinking that maybe I should conduct partial water changes every other day for the first week or so (10%-15%). Is this advised at first, so as to allow the bacteria to grow, but to rid the tank of excess ammonia/waste/etc.? Also, about how quickly will I see algae grow? I know algae is good (up to a point), but how much is good, how much needs to be removed?

Lastly, my fish are still timid (it's been about 2 days and a night). When should I expect them to swim about more and eat more?

If the fish are slow to not moving and just laying on the substrate that is a bad sign of high co2/ammonia and so on.


I would add lots of fast growing plant like anacharis to suck out he ammonia and co2 and return oxygen.


in the order of 10-15 bunches of anacharis in a 15g tank.


But than I use the procedures in the link of my signature.


I would also not add food for several days to help also.


my .02

I am setting up a new tank and going to try fishless cycling again