How many fish

[ditron]

Hi guys...
Was wondering how many small fish (tetras, plates, mollis) i can keep in a planted 40gal (150lt) tank...thanks

 

[otterblue]

You'll get good answers from people more experienced than me, I was just going to say that mollies can get kind of larger and can be somewhat aggressive to other fish. They're not neccesarily good candidates for a peaceful community tank.

 

[Sgooosh]

You'll get good answers from people more experienced than me, I was just going to say that mollies can get kind of larger and can be somewhat aggressive to other fish. They're not neccesarily good candidates for a peaceful community tank.

yes.
tetras are also nippy to big fin guppies and stuff

guppies will breed A LOT in a community tank so each 3 is actually different

you can probably have around 10 big guppies in there (ther will be smaller and baby ones)
maybe 15 neons?

mollies grow super big too

 

[Colin_T]

What are the tank dimensions (length x width x height)?

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

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Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, most tetras, barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Most common livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

------------------
How often do you plan on doing water changes?
How much water do you plan on changing when doing a water change?

How often do you plan on feeding the fish?
What are you going to feed the fish?

How well planted is the tank?

What sort of filtration is on the tank?
Has the filter been cycled yet?

These questions all relate to how many fish you can keep in an aquarium. If you only have 10 neon tetras in a 4 foot tank, and you feed them 10 times a day on live and frozen fish foods, and you do a 10% water change once a month, then I would say no more than 10 neons.

If you have an established biological filter, feed the fish a little bit of dry food once every couple of days, and do a 75% water change and gravel clean the substrate twice a week, you could have 200 neons and maybe some other fishes.

It comes down to tank dimensions (length x width), food going in, water changes to keep the tank clean, and fish compatibility.

 

[itiwhetu]

What are the tank dimensions (length x width x height)?

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

-----
Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, most tetras, barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Most common livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

------------------
How often do you plan on doing water changes?
How much water do you plan on changing when doing a water change?

How often do you plan on feeding the fish?
What are you going to feed the fish?

How well planted is the tank?

What sort of filtration is on the tank?
Has the filter been cycled yet?

These questions all relate to how many fish you can keep in an aquarium. If you only have 10 neon tetras in a 4 foot tank, and you feed them 10 times a day on live and frozen fish foods, and you do a 10% water change once a month, then I would say no more than 10 neons.

If you have an established biological filter, feed the fish a little bit of dry food once every couple of days, and do a 75% water change and gravel clean the substrate twice a week, you could have 200 neons and maybe some other fishes.

It comes down to tank dimensions (length x width), food going in, water changes to keep the tank clean, and fish compatibility.

Don't argue with @Colin_T he knows his stuff. Please don't come back and say some website says it will be fine.

 

[xxBarneyxx]

Welcome to the forum!

As Colin said the exact stocking that will work in your tank will depend on your water parameters and tank conditions. Knowing the Water hardness and PH will be the first step in figuring out what fish are suitable.

A lot of fish can work well together, however a lot will also have major issues being in the same tank. That's one of the reasons why the basic rule of "X" inch of fish per gallon doesn't work so great.

https://aqadvisor.com/ is an "ok" place to start. However be aware that is is very far from perfect and just because it says something is ok doesn't mean that is true. There are a lot of finer points that it misses which could cause issues if taken as 100% accurate.

It should not be considered the end point of planning a stocking list but the starting point of researching what fish you might be interested in.

Personally for a tank this size, assuming well planted, good filtration and good tank maintenance, I would be looking at 30-50 "tetra type" fish and maybe 2 or 3 "centerpiece fish". Could switch 10 of the "tetras" for a group of cory's and maybe have a bristlenose pleco as well.

That is a very rough guide though and will depend on your water parameters and which fish you pick.

 

[Bruce Leyland-Jones]

Both @Colin_T and @xxBarneyxx make good, sensible points.

So you've learned what your water is like.
You've even learned what fish will be able to thrive in that water.
You'll still have dozens of fish to choose from, so where do you start.

One way is to look at the tank in different sections;
Bottom, Middle and Top...then perhaps with one, or a pair of what we refer to as 'show piece' fish.

Here are the mixes in my two tanks, lower layers first...
South American-themed tank;
Bristlenose catfish
Pygmy Corydoras
Nerite snails
Glowlight Tetra
Black Neon Tetra
Golden Pencilfish
A pair of Cockatoo Apistogramma.
Note that all bar the snails will explore all of the water.

SE Asian-theme tank;
Panda Garra
Kuhli Loach
Assorted shrimp
Nerite snails
Cherry Barbs
Copper Harlequin
Chili Rasbora
Dwarf Gourami
Note that only the Harlequin stay in the middle of the water.