Hello, I am a relative beginner and the thread below tells the story of trying to get my 20 gallon tank cycled, which I believe finally completed a little over a week ago. I never knew how much I would like the color yellow until I got an ammonia reading with no green. Parameters have been 0/0/20-40 for well over a week. I called the manager of the closest good lfs and had a long talk with him about the whole saga. He suggested I add a bubbler, which I did, thinking maybe CO2 poisoning in the night. He also assured me it was OK to add some fish since the 5 danios in there are doing very well, except for staying mostly at the bottom when the light is on. I fell in love with Black Phantom Tetras and added 4 of them on MOnday. For a couple days all seemed well, the two species were interacting peacefully and everyone was swimming around freely, although mostly near the bottom when the light is on. Then, starting yesterday morning it seemed like the tetras were hiding, staying still behind plants and just treading water. The Danios seem fine. Readings are stable. I don't think I can stand it if those beautiful little things become my latest victims. When I bought the kit, I went with a flourescent light because I was told it was best for the plants. Is it possible the light is wrong for the fish? They all seem to stay near the bottom most of the time, even the active danios. Thanks for any help. I'm a basket case. Feel Terrible....what Am I Doing Wrong? Ann
I second this but also keep an eye out for the strength of the current, that kept my cardinal tetras reclusive in a corner until I figured out a way to reduce it. ALSO, more tetras will make them more confident to venture out into the light. I upped my numbers to 15 from 9 and they are finally in the mid/upper water column, like for the first time ever.
There are about 10 plants in there, a couple java ferns, 2 anubias, two big stands of anacharis, big clump of java moss, 2 swords. I'd be happy to put in more, just not sure where. I am planning to get something that floats, maybe hornwort? Thanks, Ann It's funny, no one goes near the current except the mystery snail who seems to enjoy bobbing around in it for awhile. What did you do to reduce your current? I also read that running it just at night takes care of the CO2 problem. Does that sound right? Thank you, Ann
Run the filter 24/7 with the only exception being during a water change. But for changing the amount of current, that can take some fiddling... I swapped to a spray bar on my canister filter but still the flow was too strong, so I directed it against the back of the tank so the water flow was more diffused (because of a suggestion from another fishlore member) I know tetra are agile swimmers and all, but my impression is they don’t like to keep fighting a current so they will hang out where there’s less resistance. I think I exhausted some of the tetra when I first had my tank setup so that it was a water vortex lol. If you have a HOB filter I have seen some DIY tricks with a water bottle cut in half and put under the flow to disperse the outflow, but I am only personally familiar with canister filters.
Thanks, I think I can turn the stone on its side so the current is less strong into the main water area. The snail is going to be bummed, though. Ann
There is current coming from the HOB filter, but it's not that strong. I added a stone bubbler, per the lfs recommendation to suppress possible CO2 poisoning happening at night. It's at the pther end of the tank and makes a pretty strong current/wall of bubbles. Thanks, Ann
When I tested the water today, there was a touch of green in the ammonia tube. I wouldn't even call it .25, but it wasn't straight yellow. I changed 30% of the water, dosed Prime and bingo, the tetras are out and about. The one that was a bit faded even got his vibrant color back. Did the ammonia go up because of adding the new fish on Monday? Am I not in fact cycled? Do you think the tetras would be happier in a bigger group? How will I know when it is safe to add them? I thought calculus was hard.... Thank you, kind fish people.
The ammonia will go up and the bacteria will need to adjust every time you add fish. That's normal. Usually by the time the temporary detox effect from Prime wares off, the bacteria has adjusted, and you're good. Yes, Tetras, like all schooling fish, are happier the bigger the group they're in. It's much better to get a larger group of one species than it is to get several small groups of different species. People say you need to have "at least 6". Keep in mind, that is the bare minimum number for a schooling or shoaling fish. Like, if you have room for 12 schooling fish, I would get 12 of the same kind instead of 6 of one and 6 of another.
Thanks so much. I will keep an eye on the ammonia and keep up with changes. I hear you about school size. There were only 4 black phantom tetras in the store and I kind of fell for them. I have 5 danios so I think I could add 8 more tetras into a 20. I'm guessing not 8 at once, though?
I would add them altogether once the filter is matured. Everytime you add fish you rock the boat so I want to keep that to a minimum. And they are small fish especially when juvenile.
@Ann Constantino - glad you have resolved the problem and that you now see how much ammonia affects your fish without any damage or loss. Just a word on CO2 and water flow as they are somewhat related to each other. When it comes to CO2, yes plants do produce CO2 in darkness, so the more plants you have, the more CO2 you will get in the tank at night. However what is important to understand is that you have two layers in your tank with an invisible line that separates the CO2 higher concentration zone from the O2 higher concentration zone. CO2 will tend to be in higher concentrations at the bottom of the tank and O2 at the top of the tank because CO2 is the heavier of the two gases. Why is this important to know? Because if you have a high concentration of CO2, then your fish will tend to hang out at the top of the tank as then will instinctively go to the zone with more O2 to breath. Now we come to water flow. CO2 gets removed from water at the surface of the water in the tank. By using an air stone in a tank what you actually do is cause ripples on the surface of the water. These ripples increase the surface area of water that is in contact with the air, so the CO2 leaves the water into the air above the water quicker. That is the primary purpose of an air stone, however an air stone does increase the movement of water within the tank, however it is a very "local" vertical movement around the rising bubbles from the air strone. What I would do if I were you is adjust the level of your HOB filter to either increase or decrease the water agitation at the surface of the water in the tank and remove the air stone. This will reduce the movement of water within the tank and keep the stronger water movement near the filter for fish to play in and "silent water" on the opposite side to the filter for fish to rest in.
I think 12 tetras would be a bit much in a 20 with the danios. The danios are also schooling and would appreciate a larger group. I'd do 8 tetras and 8 danios total.
I agree.... The general rule of thumb of an inch of fish per gallon can be applied - but you need to assume an inch of fish by the time they grow up and not when they are very young So a total of 16 tetras and danios should be ok.
You shouldn't ever apply that method. The op has 2 schooling fish with not a big enough of a group. You have two mid dwellers and they can't compete for space so they have to go somewhere else. I would say get rid of one school and up the other school. That would give you a chance to get a center piece fish.
Thanks. That makes sense. For whatever reason, the danios have always hung out at the bottom. This morning the tetras are all out and about in the middle, but they are not together. Thanks. Is there a way to know when the filter is mature enough to add more fish? Stable numbers for X number of days? Wow, so much to learn. Thanks for the detailed info on gases in the tank. Do you mean that I would slide the HOB up to decrease the agitation? I'm wondering if perhaps I had no CO2 problem at all. My fish have never hung out at the top. In fact they have all hung out at the bottom when showing stress, especially the danios that made it through the apocalypse.
I don't believe you have had a CO2 problem from what you have written...... Like I said, this is a matter of balance between surface agitation and water movement within the tank. I don't use air stones in my tank, but I am very conscious of water movement within the tank (like shaking or stirring juice well before you drink it). I would prefer to have a lot of water movement within the tank then lots of surface agitation as once you have the water moving within the tank, then the water at the surface is constantly being changed so the gases get exchanged anyway.
I would build my schools up slowly, 2-3 fish each week. Adding 7 more fish to a cycle handling 9 right now will almost double the ammonia output. Your cycle will struggle and you’ll have an ammonia/nitrite spike. I recommend filling out you schools out one at a time, weekly. Add 4 more black phantom tetras, then wait a week and add the 3 more zebras if that is what you are going to end up with. Better yet, 2 one week, 2 the next, then 3 to fully stock. Slow is better and will have less impact on your fish.
