Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Gav on October 17, 2014, 08:04:00 PM

Title: Time to add more fish?
Post by: Gav on October 17, 2014, 08:04:00 PM

I'm currently now almost 3 weeks into a fish in cycle with 10 Cardinal tetras in the tank. I followed the advice from the shop and started the tank with API  quick start. I added the fish after 4 days, also as instructed by the shop and added more quick start as per the instructions.

I've been testing every day and doing 15% water changes every day or 30% if I missed a day. The ammonia has never been higher than 0.5ppm and the nitrite seemed to peak at 1ppm the middle of last week.

Now on Monday evening I did a 30% change and took readings at Tuesday lunchtime, Ammonia  less than 0.25ppm, Nitrite 0ppm, Nitrate 10 ppm. I did the same again in the evening with the same results and they've stayed the same all week. My local water has an average Nitrate reading of 7ppm and my water is soft. The tank is a 90l Fluval Roma with the U2 filter.

So my question is would I be ok to add some more fish this weekend and if so how many? I'd really like 5 banded barbs but they liked to be kept in larger numbers. A bit stuck as what to do. Any advice appreciated.

Title: Re: Time to add more fish?
Post by: Sue on October 17, 2014, 08:59:17 PM

With fish-in cycling, you need to keep ammonia and nitrite below 0.25ppm. Once they have been zero for 7 consecutive days by themselves (ie no water changes needed) you can get more fish.

You have 10 cardinals, so it is safe to get as many fish as are equal in body mass to 3 or 4 cardinals - a third of the fish already in the tank. Now that you have enough bacteria to deal with the ammonia made by the cardinals, and the nitrite made from that ammonia, it won't take long for them to multiply when adding new fish as long as you don't add too many at once. You could get three 5-band barbs next - they are a bit chunkier than cardinals - wait till you've had a week of zeros again, then get three or four more and so on till you've got the number you want. Every time you add fish, the next addition can be bigger.

Title: Re: Time to add more fish?
Post by: Gav on October 17, 2014, 10:00:30 PM

Thanks, that's just what I was hoping to hear  :D

I suppose the barbs will be ok in smaller numbers until they get a few mates,  happier than they would be in toxic water anyway.