Cycling with one fish?

[Jared Learn]

Okay update on my tank. Deanasue I did like you said and went and got tetra safestart+ 2 days ago and out of the entire bottle. That seems to have done the trick as my ammonia is hovering right around zero. It seems to have skipped the night right step and gone straight to nitrates which I have read that it can do with tetra safestart. Nitrates are 10ppm. Going to give it another day or two and then do a 50% water change and then start adding fish does that sound right? Thank you all for your help is appreciated.

 

[Naughts]

Yay! Bring on the fish!

 

[Jared Learn]

Okay so now that my tank is cycled I have one dwarf gourami in the tank that is all. I was thinking of six Panda Cory's and either six emperor tetras or six Black phantom tetras. Any thoughts suggestions corrections?

 

[Byron]

Okay so now that my tank is cycled I have one dwarf gourami in the tank that is all. I was thinking of six Panda Cory's and either six emperor tetras or six Black phantom tetras. Any thoughts suggestions corrections?

First, this is a 20g long, so the base dimensions should be 30 inches (75cm) by 12 inches (30cm). This length allows you some latitude with fish that a basic (high) 20g would not, but it is still a small space.

From the other thread the GH is around 3 dGH, very soft, so that is fine for the fish being discussed here.

The cories are fine, but add a couple more. Panda cories are even more sociable than some other cory species, and a group of 7-8 would be fine here. I assume you have a sand substrate. And the temperature should be around 75-76F (24.5 to 25 C) as this species prefers cooler rather than warmer water.

The Black Phantom tetras are OK, again a couple more so a group of 7-8. Aim for a mix of male/female (they are easily discernible by the red adipose and anal fins of the female, all black/grey fins on males), 4 males/3 females or 4/4. These are quiet fish that will remain in the lower half of the aquarium.

Emperor Tetras are not a good idea here. First, they are more active, sometimes very active, which can bother gourami. Second, they really should have more length for swimming. And third, they can sometimes get a bit feisty (nipping fins too) with sedate fish like gourami.

There are many other tetras that wuld work, or some of the pencilfish, and hatchetfish. The pencils and hatchets will add interest to the upper level which will balance the cory/phantom better so everything is not staying in the same area of the tank. Ask about individual species first, as not all are as peaceful as some of them.

 

[Jared Learn]

That is all great information. I was not aware of that about the emperor tetras I looked them up on seriously fish and it said they were peaceful like the black phantoms. But Byron you know your stuff. Pencil fish or something I haven't thought about that's an idea. Would you be able to steer me towards some other peaceful tetras also just to give me and idea please. and my final question is are you saying I would be able to have the cories the phantoms and another school?

 

[Byron]

That is all great information. I was not aware of that about the emperor tetras I looked them up on seriously fish and it said they were peaceful like the black phantoms. But Byron you know your stuff. Pencil fish or something I haven't thought about that's an idea. Would you be able to steer me towards some other peaceful tetras also just to give me and idea please. and my final question is are you saying I would be able to have the cories the phantoms and another school?

The tank size is a factor here. The Emperor really needs more space as it is an active swimmer. In smaller space, such fish frequently (but certainly not always) can get a bit nippy of sedate fish. I think other options carry much less risk.

Most of the tetras tend to stay in the lower half of the aquarium, with a few exceptions. Given the gourami, I think the pencilfish like Nannostomus eques might work better for the surface area. And/or the hatchetfish, especially the smaller species in Carnegiella like the Marble, C. strigata.

Active fish also have a higher impact on the biological system, and in smaller tanks that means less fish. The pencilfish and hatchetfish species would be less of an issue.

The penguin tetra is an upper level fish, though larger than the pencil and hatchet.

 

[Jared Learn]

Okay so emperor Tetra is off the list no problem. As far as pencilfish I'm looking for something it doesn't get too much bigger than three maybe four inches as an adult. I do like the pencil fish and that is definitely an option. I don't have an actual reason but for some reason I just don't like hatchet fish that much

 

[Jan Cavalieri]

Is there another tank you can move the fish to? Then try cycling with pure (no detergent) household ammonia - it still took my tank 4 weeks to cycle but without risk to any fish. No need for water changes either in most cases because you don't have the waste created by the fish and their food. You can also cycle with fish food but I've heard that can take even longer and you may have to do water changes before the cycle is complete because the amount of waste makes the nitrates so high. I am just a novice - but this worked well for me on both my 29 gal tanks.

 

[Essjay]

I would be concerned that a tank which is cycled for one dwarf gourami only might not have enough bacteria if you add another shoal of fish. You mentioned earlier in the thread about getting live plants - did you get any? These would help to deal with the extra ammonia made by extra fish.

When you get the next fish, you need to check ammonia and nitrite daily and do a water change every time you see a reading above zero. While there may be enough Tetra Safe Start left, there may not be. Better to check and find there are enough bacteria than not to check and have the fish suffer.

 

[Colin_T]

I would be concerned that a tank which is cycled for one dwarf gourami only might not have enough bacteria if you add another shoal of fish.

I wouldn't worry too much, the filter bacteria can double their numbers every couple of hours. As long as the filter has actually cycled, the bacteria will reproduce and quickly build up in numbers to cover any ammonia produced by new fish that are added to the tank.

 

[Essjay]

I wouldn't be concerned if it was a case of doubling or even tripling the fish load, but adding a shoal of at least 6 fish to a tank with just one means that I personally would check the levels just for peace of mind

 

[Jared Learn]

Yes I did add a few plants to start and I I'm only going to add three fish to start off.

 

[Byron]

Yes I did add a few plants to start and I I'm only going to add three fish to start off.

If you intend a shoaling species (any of the tetras, rasboras, pencilfish, etc) then you should add the entire intended group together at the same time. The fish will be much less stressed the more of them there are together. Do not add three, then three more, etc of a shoaling species.

There is not going to be any issue with ammonia/nitrite here as we have all been saying.

 

[FishGuest5123]

Okay update on my tank. Deanasue I did like you said and went and got tetra safestart+ 2 days ago and out of the entire bottle. That seems to have done the trick as my ammonia is hovering right around zero. It seems to have skipped the night right step and gone straight to nitrates which I have read that it can do with tetra safestart. Nitrates are 10ppm. Going to give it another day or two and then do a 50% water change and then start adding fish does that sound right? Thank you all for your help is appreciated.

If the nitrates stay at 10ppm I wouldn’t do the water change yet. That’s a safe number for the fish. Slowly add a few fish at a time and continue testing your water. If the water climbs to 20 ppm or above then do a water change. Otherwise, just do weekly cleaning and 70% water changes and you should be fine. Good luck and keep us posted.