Adding Fish

[Squid]

so.. just thinking ahead..

Lets say, ive done my fishless cycle, added a load of fish, checked the stats and they fine (i.e ammonia/nitrites 0 and nitrates 10ppm) and later on i decide to add more fish.. Now, i know you shouldnt add too many at once as this would cause a mini-cycle and upset the balance, so you should only add a few at a time. Surely no matter how many fish you add the ammonia/nitrites levels will rise slightly. What is the best thing to do when adding fish to an established aquarium to limit the impacts on the old and new tank-mates.

Alot of the topics talk about cycling the tank in preparation and what you should do, im just still a little unsure about what happens after. I have been told that even if you fishless cycle, you shouldnt add in the full amount of fish in one go, so you have to come across this at some point. I.e my LFS said to add the small angelfish in after the other fish, so that they are less territorial..

Cheers
Squid

 

[rdd1952]

The size of the mini cycle obviously depends on how many fish you add but also is dependent on how many fish you already have. If you have say a 10 gallon tank with 4 fish and add 2 more, you have increased your bioload by 50% (assuming the fish are reasonable equal waste producers) so the mini cycle would be pretty big. On the other hand, if you have a 90 gallon tank with 40 fish and add 5, you have only increased the bioload by 12.5% so the mini cycle would be smaller. Also, since you already have a larger bacteria colony in the bigger tank, the time requied for the bacteria to catch up would be minimal. Actually, I doubt you would even notice a mini cycle in the 90 gallon if you simply added 5 fish.

As for adding all your fish at once, I strongly believe that if you do a full fishless cycle, you would be able to add all your fish at once without any problems, provided, some of those fish aren't the very delicate type. Unfortunately, I can't say this from personal experience since I couldn't find all the fish I wanted for my 75 gallon at the same time so I had to add part of them and then the rest later.

 

[Squid]

Thanks.. that seems to make perfect sense as ever rdd !