Nitrite Issue

Prime should only be used to treat new water rather than as a 'medication'.


A few questions just to get things clear in my mind -
Were you doing a fishless cycling, or intending to use the plants to do a plant cycle?
If it was a fishless cycle, how far had you got?
How many plants did you move, and what type of plants - slow growers like java fern or anubias, or fast growers like stem plants and floaters?


Plants use ammonia as fertiliser, and they don't turn it into nitrite or nitrate. They can use nitrate and nitrite in the water but they prefer ammonia as they have to convert nitrite & nitrate back into ammonia to use it and that takes energy. What I would do is a big water change to get rid of the nitrite, or several small ones if you don't want to upset the fry, and use Prime to dechlorinate the new water. Then treat it like a fish-in cycle and test every day, doing a water change if ammonia or nitrite rise above zero. With one baby fish, there should be very little ammonia being produced and the plants should be more than capable of removing it.


Shrimps do not create much ammonia either. I have a shrimp tank, a 23 litre cube. I have a piece of wood with anubias bonsai, another piece of wood with java fern and some Schismatoglottis preitoi (looks a bit like anubias which can be planted) These are all slow growing plants. But I also have red root floater on the surface and floating plants are particularly good at taking up ammonia.
About a month ago I changed the filter. Literally just took the old one out and put a new one in. I did not use any mature media from the old filter. The shrimps did not seem to notice, and they would have done if there had been a trace of ammonia or nitrite. The testers didn't register any either. I know there are bacteria in the substrate as there are in any mature tank, but the plants, especially the floating ones, would have removed a lot of ammonia, if not all of it.

I would treat your tank as now doing a plant cycle. Water change(s) to remove the nitrite in there now, and plants to do the rest. If you haven't already got some, I do recommend floating plants for shrimps and they are very good at ammonia removal.

With a fishless cycle, it does take longer to grow nitrite eaters than ammonia eaters. The nitrite eaters can't even start to grow until the ammonia eaters have started making nitrite so they are always one step behind. And nitrite eaters multiply slower than ammonia eaters which means it takes longer to grow enough.

Since plants remove ammonia and don't make nitrite, you can cycle a tank using plants rather than bacteria. With just 1 fry, there will be so little ammonia made than the plants will take up all of it before the ammonia eaters you've grown have chance to grab it. And there'll be no extra nitrite made, just what's left from the fishless cycle. That's why I've suggested doing as many water changes as necessary to remove all that nitrite then leave the plants to do the job rather than trying to grow more bacteria.
And then the plants will establish themselves and start to grow so they'll be able to take up even more ammonia, so once there's lots of new growth you'll be able to get the shrimps.


A couple of years or so ago I saw some fish I'd been wanting so I came home and set up my quarantine tank. I took some media from my main tank and added ammonia to test that there was enough mature media. It turned out there were so few bacteria in the mature media that I ended up doing a full 6 week fishless cycle - by which time all the fish had been sold. So next time, I didn't use any mature media. I put a filter in the tank, filled with brand new filter wool, just to move the water round and catch any bits. When I bought the fish I also bought 2 bunches of elodea and left the stems floating. I also took some floating plants from the main tank. There were 12 kuhli loaches in that 25 litre tank and I never saw a trace of ammonia or nitrite.
One cory fry is a lot less bioload than 12 kuhli loaches.