40 litre tank - what type of fish and how many?

Hi all, I’m new to fish keeping but I’ve been trying to educate myself as much as I can. I’ve set up a SuperFish Home 40l planted heated tank and was wondering what fish you would recommend and how many. I’m leaning towards neon tetra as they seem the easiest to take care of and lovely and bright, am I right that I should have at least 6 for them to be happy?
I would also like a small shrimp to clean the bottom, what breed would you recommend?
Would 6 tetra and 1 shrimp be happy in a tank this size?
Thank you in advance ?

Just so everyone knows what the tank is, it's 47 long x 25 wide x 42.5 cm tall (18.5 x 10 x 17 inches). It's a tall tank that is narrow front to back.


@AbbyLou94 The first thing we need to know is the hardness of your water. Fish have evolved in places all over the world; some places have hard water while others have soft water. We should aim to keep fish which come from roughly the same hardness as our tap water.
Looking at your location I see it is London. This means it is likely you have very hard water, though that's not totally certain. Can I ask you to look on your water company's website for 'hardness'. There should be a page where you enter your postcode. Tell us the number and the unit of measurement as there are several they could use.



Neon tetras are soft water fish. They are OK in water up to middling, but not in hard water. This is why you need to check your hardness. There fish which would be suitable for your tank and hard water, if that's what you have.


Red cherry shrimps are the easiest type and are fine in both soft and hard water - but they like company so more than just one

Thank you for that information, I checked my postcode as suggested and these are the figures given
Calcium - 122 mg/l
Total hardness - 305 mg/l (which I think is pretty hard?)
Degrees English - 21.35

Is there a way to soften the water without installing a fancy (and probably expensive) softener. I had a quick Google and it keeps recommending the Tetra Aquasafe but I can't find any information about it softening water just 'improving water quality', is this any good?

I have ordered some pH test strips as I know this may also affect the types of fish I can keep

Any suggestions on hard water fish instead of Tetra? Preferably I would like schooling fish

AbbyLou94 said:

Thank you for that information, I checked my postcode as suggested and these are the figures given
Calcium - 122 mg/l
Total hardness - 305 mg/l (which I think is pretty hard?)
Degrees English - 21.35

Is there a way to soften the water without installing a fancy (and probably expensive) softener. I had a quick Google and it keeps recommending the Tetra Aquasafe but I can't find any information about it softening water just 'improving water quality', is this any good?

I have ordered some pH test strips as I know this may also affect the types of fish I can keep

Any suggestions on hard water fish instead of Tetra? Preferably I would like schooling fish

Click to expand...

Hard water schooling fish , mollies , platty , guppy are some of the more popular ones , I wouldn’t try and change your ph or Gh really you can soften water by having lots of natural wood but I’d stick to the tap just for ease

How many of these would you suggest for the size aquarium I have alongside a couple of red cherry shrimps?

The number you need is 305 mg/l CaCO3 - that's the same as ppm. The other unit used in fish profiles is dH, or German degrees. Your 305 ppm converts to 17 dH.


I wouldn't get either mollies or platies as they are too big for this tank. Guppies or endlers are more suitable. But I would get only males as females have a lot of fry. Even a tank of just females will result in fry as female livebearers can store sperm and use it for many months.

If this was my tank I'd go for several male endlers in different colour patterns and red cherry shrimps.
You will need hiding places for the shrimps as they have to shed their skin to grow and until the new skin hardens they are very vulnerable. You photo looks like it is well equipped for shrimps