So, I know i'll probably be flamed for not doing a fishless cycle...but I'm gonna present my issue anyways.

I have a rather new 75 gallon. I needed a place to put some of my friends 10 Zebra Danios, so I figured I would use them to cycle my tank. They've been living just fine for about 3 weeks. Didn't lose any...none even look sick.

So here's what happened:
I KNOW I want some Roseline sharks in my tank, and the only place that ever has any is an LFS by my house. I've looked around for 20 miles, and they're the only ones that ever carry them.
I was looking around in the store and they said that the Roseline Sharks that they had were the last ones they said they were getting for a long while.
I had to jump on them. I took 3.
I got home and took out all the Zebra Danios (took them back to the store) except 3. And I put in the Roseline Sharks.
So right now I have 3 Roselines and 3 Zebra Danios in a 3-week-old partially-cycled 75g tank. My API test kit is on the way from Amazon so I can carefully monitor the conditions of the tank.

So do you think they'll survive? I know I'm playing around with fishy-lives here, but I really wanted them....
When I get my test kit what should I make sure the ammonia levels are under so I know when to do a water change? And should I take out the other 3 zebras?

Any advice would be great.

Thanks!

This is my opinion, although there may be some to disagree.

I see no reason to take out the other zebras.
At three weeks, you should be already cycling the ammonia into nitrItes, so it likely isnt going to be getting very high.
Still keep a watch on it.
I'd do a PWC if you see ammonia over .5 and nitrites over 1.0, and feed only once every other day.

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150G, 1 shovelnose sturgeon 8", 1 polypterus endilicheri 9", 1 leopard ctenapoma 4", 1 Distichodus Sexfasciatus 6", 1 Farlowella acus algae eater 8", 2 silver dollars, 2 tank bred angelfish, 1 clown knife 11", 1 Jaguar hybrid syntadonis 4", 6 African cichlids 3+"

I agree meBMme feed every other day and sparingly.
take a water sample to the store and have them test it.
if you have access to another established tank take some gravel from the old tank and put it in some stocking and put in the new tank.
This will help jump start the new tank.
I have used an filter cartridge from a smaller tank that is older to jump start the new larger tank and it worked great,

Probably was a good idea to take out some of the bio-load over adding more. The fish can live through it, but you need to stay on top of the conditions. I agree that you probably are at or near the point that ammonia is already getting processed, but the nitrites could be soaring on you in no time....still it should be a fairly light bio-load, so hard to say. If you haven't tested the water since you put fish in, I would do a 50% water change...depending on how long it will be before your test kit arrives. If ammonia or nitrite is above 1 do a water change. If 1 or below, leave it. If fish are showing any signs of distress during any time, perform a water change.

Thanks for all of the info. SO far so good, and my test kit will be here tomorrow.
So any ammonia over 1 do a change? or .5?

I go by 1ppm. Others may go by .5ppm. Use 1ppm as your guide and if you see signs of distress, do a water change and lower the threshold.

I agree with Ben. If you're really worried, you can do a 25% WC if the ammonia or nitrites are at .50ppm and for readings above that I'd do 50% or so.... and like Ben said, if they are ever showing signs of stress or ammonia/nitrite poisoning, do a large partial WC.

I would also do about a 50% WC now, like Ben said, since you haven't tested since putting the fish in.

(Once your cycle is done, you will need to either add more zebra danios, or re-home the 3 you have, since they are a schooling fish and need 6+.) You could also add another Rosaline Shark or two if they ever become available, as they are also schooling fish, (3+ for them,) but, they do get to be 6" tops (sometimes just 3-4 inches) so make sure you have the room.

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Thanks for the info all. My testing kit comes in the mail Wednesday. I just did a 25% WC just to be safe until then. So far everything looks good.
I will be re-housing the Danios as soon as this part of the cycle is done, and be adding some other fish. I don't really plan on getting more Roselines..I think 3 may be enough to school..and i know they get big.

So my tentative plan is:

3 Roselines
7-8 Cories
Maybe 5 Rainbow Fish?
And maybe 2 Angels

I'm not 100% sure the Angels are ok. Not sure if they'll get along with the others.
ANy advice there?
Also, if that is my plan, what fish would you add next to continue the cycle once the ammonia levels have been 0 for a while?

Thanks!

I have kept angles for years and the only problems you will have is when they spawn.

I tried everything to try to keep them from spawning but like clockwork they would spawn at a drop of a hat.

So I just kept a pice of slate in the tank and a spare pice in a 10 gallon breeder tank. When they spawned I would swap the slate and raise the fry in the 10 gallon.