20 Gal High Stocking Options

[Alison T]

I've got a live planted 20 gal high aquarium that I want to restock. Right now it has 4 mollies and a baby bristlenose pleco, but, as I'm having problems with them, all four of the mollies are going to be returned soon, and I'm still considering what to do with the pleco (I will either return him or move him to a bigger tank when he is larger). My plants are flourishing, and my water parameters are close to perfect.
I want to know what some appropriate stocking options would be for my tank? I'm interested in long-fin serpae tetras and kuhlI loaches, but I'd love to hear some other choices.
(Also the driftwood is a cave itself and there is another cave in the back of the tank that isn't visible in the pics.)

 

[endlercollector]

How hard is your water? Soft is better for tetras and hard is better for livebearers. Also, just what trouble have you had with the mollies? There's a silhouette of a molly in one photo that looks a bit gaunt. Is it sick? BTW, the tank looks lovely--the plants pop nicely against the dark substrate.

 

[Alison T]

How hard is your water? Soft is better for tetras and hard is better for livebearers. Also, just what trouble have you had with the mollies? There's a silhouette of a molly in one photo that looks a bit gaunt. Is it sick? BTW, the tank looks lovely--the plants pop nicely against the dark substrate.

How do I test for how hard the water is? And the problems I've had with the mollies are that a few of them have died from an undetermined cause (although they seemed lethargic when I got them), and I have a single male in the tank, so I have quite a few fry on my hands rn. Also It doesn't help that a few people have told me that 20 gal h isn't an ideal size for mollies. Which pic is the sick-looking molly in? These pics are from their first few days in the tank.
(Also thanks for the compliment, I worked really hard on the tank!)

 

[endlercollector]

How do I test for how hard the water is? And the problems I've had with the mollies are that a few of them have died from an undetermined cause (although they seemed lethargic when I got them), and I have a single male in the tank, so I have quite a few fry on my hands rn. Also It doesn't help that a few people have told me that 20 gal h isn't an ideal size for mollies. Which pic is the sick-looking molly in? These pics are from their first few days in the tank.
(Also thanks for the compliment, I worked really hard on the tank!)

You can just look up your city's water information online or call, and they'll be able to tell you the pH, KH, and GH if you don't have the test kit for that. It's the very first photo that has a sickly looking molly in it in the upper left part of it. Please, never buy lethargic fish in a store. Watch them carefully, and if anybody looks pathetic, don't buy anything in there at all because the tanks typically share filtration.

Anyway, I'm hesitant for you to put new fish into a tank where others have died as they may catch whatever it was. That's why it's generally a good idea to quarantine first. I know you're setting up this tank, so that's hard to do. But if you can set up a 10-gallon quarantine with no substrate, it'd be a good thing to do. You have several options here.

1) Return these fish and put in new ones, just taking chances. It may work out, it may not.
2) Return these fish and do a complete tear down.
3) Return these fish, throw out the filter media, gently uproot the plants and pour some potassium permanganate in there, letting it run for a few days till the water clears before rooting the plants again. It won't get rid of anything deep in the substrate, but it will get rid of a lot of stuff. You can use some BB in a bottle, such as Seachem Stability, to get your filter going again.

 

[Alison T]

You can just look up your city's water information online or call, and they'll be able to tell you the pH, KH, and GH if you don't have the test kit for that. It's the very first photo that has a sickly looking molly in it in the upper left part of it. Please, never buy lethargic fish in a store. Watch them carefully, and if anybody looks pathetic, don't buy anything in there at all because the tanks typically share filtration.

Anyway, I'm hesitant for you to put new fish into a tank where others have died as they may catch whatever it was. That's why it's generally a good idea to quarantine first. I know you're setting up this tank, so that's hard to do. But if you can set up a 10-gallon quarantine with no substrate, it'd be a good thing to do. You have several options here.

1) Return these fish and put in new ones, just taking chances. It may work out, it may not.
2) Return these fish and do a complete tear down.
3) Return these fish, throw out the filter media, gently uproot the plants and pour some potassium permanganate in there, letting it run for a few days till the water clears before rooting the plants again. It won't get rid of anything deep in the substrate, but it will get rid of a lot of stuff. You can use some BB in a bottle, such as Seachem Stability, to get your filter going again.

I know that my pH is around 7.2 right now. I will look into getting a test kit for KH and GH. I've only had the mollies for a little over a week, and I'd really like to avoid having to completely tearing it down. I'll be returning the mollies (and their fry) within the next few days. I believe the molly you pointed out was the one that had just given birth, but shes one of the two that died (I started with 6).
Do you have any stocking suggestions for when I do eventually restock my tank though?

 

[endlercollector]

I know that my pH is around 7.2 right now. I will look into getting a test kit for KH and GH. I've only had the mollies for a little over a week, and I'd really like to avoid having to completely tearing it down. I'll be returning the mollies (and their fry) within the next few days. I believe the molly you pointed out was the one that had just given birth, but shes one of the two that died (I started with 6).

Do you have any stocking suggestions for when I do eventually restock my tank though?

I do have a bad feeling about that molly. I would recommend at least running the potassium permanganate through there if you don't want to do a complete teardown.

The pH sounds find for tetras. A shoal of 6 serpae tetras would look nice in there. KuhlI loaches do better with a sand substrate. Do you have dark sand or something with sharp edges? Anyway, let us know what it is as that can affect your choice of fish.

 

[Alison T]

I do have a bad feeling about that molly. I would recommend at least running the potassium permanganate through there if you don't want to do a complete teardown.

The pH sounds find for tetras. A shoal of 6 serpae tetras would look nice in there. KuhlI loaches do better with a sand substrate. Do you have dark sand or something with sharp edges? Anyway, let us know what it is as that can affect your choice of fish.

I'll definitely look into the potassium permanganate. My substrate is actually black diamond blasting sand.

 

[endlercollector]

I'll definitely look into the potassium permanganate. My substrate is actually black diamond blasting sand.

OK, that should work for the KuhlI loaches. In case you haven't already read the Fishlore page about their care, here's a link: KuhlI Loach

 

[Alison T]

OK, that should work for the KuhlI loaches. In case you haven't already read the Fishlore page about their care, here's a link: KuhlI Loach

Thanks a ton for your help.