About Half-Stocking

[kmur]

Hello! Since my cycle log is long and convoluted, I figure I'd have a much better chance having some questions about stocking answered in a new post
start

After about 8 weeks, my cycle has reached a point where it consistently hits double-0s in 24 hours, so I decided to start putting some serious thought in to stocking.

I just recently (a few days ago) went and got plants for my aquarium. I got all the plants that I intend to have, but most of them are currently pretty small, and will double in size with him. (amazon swords, crypts.) I also have some bulbs (I think Val) that won't sprout for another two weeks.

This means, while the aquarium is 'fully-planted,' it isn't very heavily planted yet and there isn't a lot of room to hide.

My stocking plan is as follows:

8 Ember Tetras
10 Celestial Pearl Danios
1 Whiptail Catfish (I can't remember the variety he is off the top of my head, but one of the varieties that rarely gets above 6")
8 Pygmy Cories (if I can find them,) or 6 of a smaller non-pygmy variety of Corey.

The Actual Question - The Celestial Pearl Danios are very timid, and I know they're a little more sensitive to changes in water parameters, and they wouldn't have much hiding space in the current growth levels of the tank. I was thinking about getting the ember tetras and whiptail catfish now, and then in a few months adding the Pygmys and Danios. (I think I'll have to have the pygmies shipped, so want to wait until it warms out outside. I'd also put a few weeks of 'buffer' between adding the two species in to the main tank.) Since the bioload of pretty much everyone in here is pretty low, I was wondering if it would put the danios / cories in harms way if I added them later, thus suddenly jumping up the bioload in the tank a bit.

This is a 30g US fish tank, sand substrate, and at the moment the plant growth only goes about half-way up the tank. There is some driftwood for the catfish and cories. The best-case scenario is that I start stocking in a week, more likely scenario is two weeks or maybe more based on the slowness of my cycle.

 

[kmur]

Well, I spent days thinking about that, and of course the second I finally say something I get an idea.

I have to set up an isolation tank for the first two weeks any newbie fish come in; after that two weeks, when I move the fish in to the big tank, I could move the filtration medium from the isolation tank in to the filter of the main tank. This would, in theory, add enough bacteria to handle the bioload of the new fish.

Lemme know if I have any flawed logic there.

 

[the_lock_man]

Interesting question, that, I don't know the answer as a definite, but my logic goes as follows

Doing a fishless cycle means that when you are cycled, you can go to your intended full stock level straight away, as you have built up more bacteria than is necessary to cope with any practical stock level.

If you then only part-stock the tank, the bacteria will die back, as they are not getting as much ammonia and nitrite - therefore you would then need to add the extra fish slowly, as you would after a fish-in cycle, to allow the bacteria colonies to grow again without getting any spikes.

Of course, my logic might be way off, hopefully Waterdrop or one the other experts will correct me!

 

[KittyKat]

You won't have problems adding so many fish to the tank: as you say, they are low bioload and you have plants. My usual course of action is to just be conservative with the feeding for the first few weeks.

Of course, until you do add fish.. the filter still needs feeding