Who Gives A Fish Forums

I'm reaching out for some advice from fellow members here.

I've recently become the proud owner of a brand new 22L Marine/Tropical tank, and I've decided to set up my dream mini-marine tank, given that I already have two tropical tanks.

I've purchased 20L of pre-cycled saltwater from an aquarium shop, and my tank is currently cycling - I'm planning to leave it for two weeks, just to be on the safe side. The tank's equipped with marine-specific sand, a thermometer, and a heater, but I haven't added any decor yet, as I was advised against it during the cycling period.

In terms of stocking, I'm thinking of introducing the following:

- Three small Boxfish
- One small Clown Fish
- One small Blue Tang
- One small Coflake
- One Rock/hiding cave

I'd love to get some advice on whether these three species of fish will get along. I spoke to a specialist at the aquarium store, and they told me that the box fish and small clown fish should be fine together, but I forgot to ask about the Blue Tang.

What else should I be aware of? I'm a bit nervous, as I've fallen in love with these fish, and the thought of losing them is unbearable!

Thanks for your input!

First off, Welcome to the salty side. I'm assuming you're not using live rock, which could lead to nutrient problems if your tank is stocked healthily - and with your fish choices, it won't be. If I've got my calculations right, 22l is about 6 gallons, and the only fish you've listed that might be okay is the clown.

Box fish are notoriously difficult to keep, and when they die, they release toxins, which can 'nuke' the tank. The tang can also be tricky, as they're very prone to ich and need a tank at least 6 ft long. And if you're keeping live coflake, you'll need very bright lighting - think T5's - and pristine water.

Honestly, your best bet might be to cut back the stocking to a small goby and some live rock, or consider a bigger tank - maybe even use the 22l as a sump? As someone who's kept tropical tanks in the past, you probably know that bigger is better when it comes to tanks, especially in marine. It's tough to keep a small tank in saltwater healthy and thriving, even for experienced reefers. A good starting size for a marine tank is usually around 20 gallons - about 75l, I believe. A tank this size will be more forgiving with water parameters, and you'll have more choices when it comes to fish.

There's a lot I haven't covered, but whatever you decide, do plenty of research from sources other than your LFS.

Thanks for your reply, I really appreciate your honesty. I've been reading up on Blue Tangs and I think I'll have to leave them out of my plans, they do need a lot of space to swim. I was wondering, would it be okay to keep one clown fish and one small box fish together in my 22L tank? Or would even just two small fish be too much for the space?

I do plan on adding live rock to the tank, but I'm not sure if I should do it while the tank is cycling or wait until I add the fish. I've got limited space at the moment, with two tropical tanks and a coldwater tank, so I figured I'd start small with my marine tank and upgrade later.

Boxfish are my absolute favorites, and I was really hoping to keep them. Would it be okay to keep two tiny boxfish together in the tank, without any other fish, until I can upgrade? I know they can be tricky to keep and I've read about the toxins they release when they're stressed or die. If I had a solo boxfish and it died, would the whole tank be affected?

I've decided to give the coflake a miss for now, and I'm glad I've got bright lighting in the tank, even if it's not being used for the coflake. One last thing, I was wondering if the toxins released by boxfish are poisonous to humans if we touch the tank, or is it just a problem for the other fish in the tank?

I do plan on putting live rock in, is it best to do that while the tank is cycling or only when the fish go in?

You actually need the live rock to cycle your tank - the water you've put in isn't cycled, it's just water, so I'd recommend adding the live rock as soon as possible to help the process along.

Boxfish are my absolute favourites, and I was wondering if two tiny ones would be okay together in my tank, without any other fish, until I can upgrade in the near future. I've always wanted a marine tank specifically for them, and I adore them, but I'm worried about keeping them safe. I've read that they can release toxins when stressed or if they die, so I'm concerned about the potential risks.

To be honest, I don't think boxfish are a good idea for your tank, and if one were to die, it could potentially kill off the whole tank. I know it's not what you want to hear, but it's better to be safe than sorry.

I do have very bright lighting in my tank, but I was thinking of giving coflake a miss for now and waiting until I have a bigger marine tank in the future.

Actually, mushrooms and lower light loving coflakes might be okay, but I'd still recommend holding off for now.

Mush be nice to have manners, so thanks for asking, and I hope this helps!

Thanks so much for your response. I will get on to putting the rock in my tank ASAP, as I'd like to stock it as soon as I can. I guess I'll have to wait a bit longer now, but I'm patient.

I'm really disappointed to hear that boxfish aren't suitable, though. I've always wanted to keep them. Maybe I should just get a clownfish and a small goby instead? I did see a tiny clownfish and two small boxfish in the same tank at the aquarium shop, so I'm not sure why it wouldn't work.

You said that boxfish could kill the whole tank if they died. I just want to know, would the toxins they release be a permanent problem, or could I get rid of them with a water change and a good filter?

Also, is the toxin they release harmful to humans? I mean, if I accidentally put my arm in the water, would I be okay?

Thanks again for your help. I really appreciate it.

I think having a clown and a blue tang in a small tank together is not ideal, they'll be moved on eventually but still, it's not the best setup.

Regarding the blue tang, I've learned they need a huge amount of space, at least a 6ft tank, which is definitely not feasible for me right now.

Honestly, I think one clown fish on its own would be a great choice for your tank, or if you want some company for it, a small goby would be a better option, they're actually pretty cool to watch and can be quite entertaining.

Honestly, the main issue with boxfish is their size - most of them grow up to a foot and a half, which is just way too big for a tank of your size. I'm also starting to think that even a clownfish might be too much for this tank. To be honest, I'd recommend going with something smaller like a few gobies or blennies - they're interesting to watch and would be a better fit for a tank this size.

I think you're referring to a Regal Tang, not just a Blue Tang - those are massive, 14" fish that need at least a 5ft tank, if not bigger. A 20L tank is really too small for a marine setup, to be honest. I wouldn't even consider putting a Clownfish in there, they're better in pairs and would need a tank of at least 60L. For a tank that size, a very small Goby is probably your only option. It's going to be tough to keep a 20L tank healthy, but I suppose it's doable - just don't expect it to be easy. If I were you, I'd aim for a bigger tank, at least 125-250L, for a first marine setup.

I think it's time to take a step back and do some serious research. I know I'm a newcomer to the marine side, but my advice would be to slow down and learn as much as you can before diving in. I spent months researching before setting up my tank, and I'm still taking my time getting everything just right. When I saw your stock list, my first thought was "no way" - it's just too ambitious for a small tank. Waiting a week and a half might seem like patience, but to me, it sounds like you're eager to rush in. Don't get me wrong, I'm not trying to discourage you, but you really need to rethink your options. Keep asking questions, and you'll get all the advice you need - this forum is full of helpful people. Take a look at aquariumdomain.com and read up on some popular marine fish profiles. It'll give you an idea of what to expect. For example, I'd love a yellow tang, but my 55g tank is way too small, so I've had to cross it off my list and look for alternatives. There are plenty of other fish out there, after all.