Hello all, yes this is my column tank.
I thought my tank was cycled, but now I tend to agree that perhaps it wasn't.
@AdoraBelle Dearheart , thank you for checking in.
Last night, I lowered the temperature, did another water change, bought and added API Quick Start and Ammo lock. After originally lying on his back, My second cory seemed to come back to life. Unfortunately he went back to in and out. My other fish today seemed extra active but the Corys, not so much. He's still hanging on though..
I performed tonight another water change. The ammonia dropped a bit, but i still have a bit to go.
To
@Flushable Pets , to answer your question about the fish, I have the 3 corys (now 2), 3 harlequins, 3 Neons, & Betta.
I'm really sorry to have to tell you this, but your tank isn't suitable for any of these fish. I'm imagining you were given advice about cycling and what fish to put in your tank by a fish store? If so, it's not your fault. The first hard lesson many people learn in this hobby is not to take the advice from the fish store that's trying to sell you fish, unfortunately. You really need to do your own research into what care requirements are for the fish you want to keep before buying them.
Keep on top of the water changes while it finishes cycling, but then please, please do some research on what tank requirements are for the species you have.
In fishkeeping, we talk about the volume of a tank a lot, and it is important. But even more important in most cases - especially in bottom dwelling species like cories and schooling species like harlequins and neons - is footprint. Meaning how large the base of the tank is, how much space they have to move around. 10 gallons is already on the small side for most cory and schooling species, but when most of that space is vertical, it's useless to them. Most fish need the horizontal swimming space. There's a good reason the rectangular shaped tanks are still the standard across the hobby - it's because it's the shape that works best for most species of fish we want to keep. Column and hex tanks look cool, but when you find out how few fish would really feel happy and thrive in them, most of us stick with the normal square or rectangle shapes.
The betta fish (and cories to some extent, but not as much) uses an organ to breathe air from the surface sometimes, as well as taking in oxygen from the water. But bettas also tend to rest a lot, often on the bottom if there are no large leaved plants near the surface for them to rest on. Getting from the bottom to the top in a column tank is a lot of work for a betta, thanks to the big fins we bred them to have, so very tall tanks really don't work for them. Bettas are also fiercely territorial and live alone in the wild, they really should be kept alone and not with other fish.
Then there's the fact that harlequins, neons and cories are schooling species, which means they need a group of the same species living with them, and the minimum amount for each species is six of them, for them to form a little school. More is obviously better. Since they swim in huge schools in the thousands in the wild, keeping them in twos or threes doesn't seem right, you know? They feel safer when they're in a group, so a neon on it's own or just three of them will feel unsafe and tend to try to hide away more, and not show the schooling behaviour we love them for.
But if you bump up the school numbers so you have six cories, six neons and six rasboras, you'd be overstocked in even a normal ten gallon tank, let alone a column. What species of cory do you have? Some get much larger than others, and would have different minimum tank size requirements. If you're not sure, you can upload a photo of the cories and people here can ID them.
But the bad news is that with this tank, even once it's fully cycled, you're still going to have problems with the stocking you have. And the betta already has fin rot? I'd highly recommend you search online second hand trade places for a decently sized rectangular tank, you can get some bargains if you look carefully, and with your current stock, I'd say no less than 20 gallons so you can give them proper schools, depending on the cory species.
If you really don't want to/can't get a different tank, then sadly, you need to consider returning or rehoming the fish you have now, and researching what fish could work in the column tank. There are a few oddball species like pencilfish that could work, and
@Byron is very knowledgeable about species that could work, but a ten gallon column tank does limit you a great deal. But the welfare of the fish has to come first, I'm sure you agree, can tell how much you love the cories already, and know you'd want the best for them. I'm sorry to be the bearer of bad news, and that you were given such bad advice.
