I've got a cycled, filtered, heated, planted 10 gallon tank with 1 betta, 3 cory cats, and 2 ghost shrimp. It's been nice and stable for about 2 months now, but this morning I noticed the cories looked uncomfortable, so I checked my parameters and found that my nitrate is between 5 and 10 ppm. My ammonia and nitrites are perfect though, both nearly 0. My betta seems fine, but my ghost shrimp look agitated. I'm doing a 30% water change right now. Is this a normal thing to have happen or is it something that I need to fix? I might be overfeeding my cories, they get about 1/3 of one of those fishy gumdrops (brine shrimp, bloodworms, or vegetable) twice a day and I've had a pretty good diatom bloom going on for a couple weeks.
Nitrates are sneaky... even once the tank is cycled, they can still rise to a toxic levels - and some critters are more sensitive than others.
Overfeeding, lack of vaccuming gravel or too much gravel (especially in a powerhead filter set-up) and lack of water changes help them rise.
The gravel can hold nasty crud for a long time. I was doing frequent water changes but had 4 inches of gravel and no undergravel filter... so it was building up and my nitrates went sky high. My betta got popeye as a result.
Bottom feeders are your 'canaries in a coal mine', and will turn ill due to poor water quality faster because they are where the toxins gather and the water is less oxygenated.
You did the right thing. Keep an eye on your nitrates, keep up on your water changes and consider if there is anywhere in the tank where the toxins could be building up.
You want your water prams to read:
Depending on the number and type of plants-with your stocking and feeding....you should have nitrate levels.....it is important to keep nitrate level below 20ppm....5-10ppm is fine and tell you that you are cycled in unplanted tanks...in planted tanks it is still okay but it can tell you that you don't have enough of the right kind of plants for self care or filtration on that stocking level......water changes and filter media cleaning will still be needed weekly.....it never hurts to make an extra water changes and any time you see behavior changes in your fish you should always make a water change to rule that out.....your DOC's may be high too......
Thanks! I've only got about 2 inches of a planting substrate, but while I vacuum the top layer weekly with my 25% water changes, I might not be getting down into where the crud is hiding. Should twice weekly water tests be enough or should I step up to every other day or so?
My cories are happy again, but my nitrates are still a little under 5. Should I do another 30% tonight to see if I can bring them down further?
I have 3 little ribbon plants, 4 of an assorted bundle of what I assume are semi-aquatic plants, and about 5 stems of anachris that my shrimp are feasting on. Should I buy myself another hornwort? I lost my last one when I had my cory fiasco and I haven't made much effort to find a new one since the shed needles were a bit of a pain. I was still finding them for two weeks after the plant was gone. I loved the way it sucked up ammonia though, and it was good cover for nervous fish.
What are DOC's? I don't think I've ever heard of those and a google search just kept bringing up "fish doctors".
Is your substrate all gravel? What size?
If your substrate is gravel, you'll want to clean it section by section in this way: After establishing suction, plunge the wand into the gravel, and use up and down motions to clean the gravel section by section. This will suck up crud with the least amount of it being churned up into the water (your filter should catch the rest).
If you haven't done this for awhile and your gravel is largish, you could have crud build-up under the surface gravel... and the bottom feeders live on top of that, and will continue to be bothered by it (the water changes helping in the short term).
The cleaning of the gravel and water changes will make the bottom-dwellers enviroment cleaner.
I would test the water more frequently when there is trouble in the tank or fish are added or there are other changes; once a week once things have calmed down.
I've got an aragonite(or something like that) substrate for my plants. I did the gravel cleaning you suggested 2 days ago and my nitrates are still under 5ppm. They're not quite 0, but my cories look happy, so I'm going to wait a week unless I see a rise in the levels before I do another big cleaning.
Do you have any suggestions of what kind of plant to put in my tank to slow this from happening again or do I just need to keep up with the thorough vacuuming?
Should I be feeding the cories twice a day or would they be happy with a feeding when I turn out their lights? They seem like they graze a little more actively in the dark and the betta can't steal as much food.
Your corys are night feeders, so feeding them at night is perfectly fine. In my community tank, if I feed the tetras flakes in the morning, the cats don't bother to steal from them. When I throw in their bottom feeder pellets and turn out the tank light at night, that's when I see them move. :)
I would continue to give the gravel good, deep cleanings. If the corys seem fine with every other week, great. If they need it once a week, you'll know by the water test and by how they're acting.
Unfortunately, I can't advise you on live plants... I go in for strictly silk. There are plenty of other people on the board who do use live plants, however. Search 'live plants' in the forum's search bar. :)
You don't need to get your nitrate to 0ppm....you do want to keep it under 20ppm however.....weekly 50% with vacuum in all areas that can be reached without moving anything in the tank or disruption of plant roots should maintain water quality and safe nitrate levels....it normal and expected to have nitrate reading...
Plants-any stem plant and floating plant are good choices.....