Miss Wiggle
Practically perfect in every way
So you've got your tank, you've got your equipment, you've started your cycle and now it's time to think fish. I've written this is a little guide to help people work out what fish to put in they're tank and some of the key issues you need to take into consideration. It's mostly aimed to a beginner wanting to build a community tank, obviously if you start getting into oddball or species specific territory then requirements will differ quite a lot from these guidelines. The main issues to think about are size of tank and size of fish, water requirements, feeding requirements, swimming levels, aggression and territoriality, group numbers and total number of fish.
One point I need to make clear before we start looking at the basic guidelines is that the requirements will differ from species to species, these rules will give you an initial idea of how to work out sensible stocking for your tank, once you've gone through the following steps and worked out a list post it up on the forum and we will give your our input and let you know if there's any problems.
Tank Size and size of fish
The first thing to think about is the size of your tank, I say this first as if you've already got the tank it's the one thing that can't be changed.
There are two factors to consider with the size of your tank, the dimensions and the total volumne.
Firstly you need to work out the biggest size fish you can have for your tank, here is a guide written by CFC one of our experienced moderators, it's written to apply to large catfish however I think the same basic rule applies. To work out the absolute minimum tank dimensions for most fish you find it's adult length the tank must be 4x this long and 1.5x this wide and tall, this gives turning room and swimming space. So for example if the fish you like is 3" long, the tank must be 12"x4.5"x4.5". Some species like angelfish need a really tall tank, some species like a lot of malawi cichlids like a long tank but aren't bothered by the height so the dimensions of the tank can be crucial.
You then need to take into account the total volume required for the fish, requirements will vary so look at the species index or just use google.
For some fish dimensions are more important, for some the water volume is more important. You should find out they're requirements for both if possible and take the larger number as the minimum tank size.
So you should now have an idea of the largest size fish you can put in your tank which will help you choose fish.
Water Requirements
Water Requirements mostly relates to the pH and hardness of water, all fish need to have 0 ammonia and nitrite and low nitrate levels. Here is a good topic explaining pH and hardness of your water.
The most important thing to remember with pH is stability is the key, most community tropicals will adapt to a pH slightly out of their comfort zone so don't panic if yours is a little higher/lower than ideal, it's better to leave it at that and have it stable than try and adjust it and have it fluctuating.
You have to make a choice at this point based on the pH and hardness of your tap water, you can either
1 - Choose fish to suit your water, so they will be happy and you won't have to try and change anything
or
2 - Change your water to suit the fish you like, bear in mind that adjusting pH is very tricky and ideally it should be done when the tank is cycled but with no fish in, so you would need to complete a fishless cycle (don't try and adjust it while cycling, the high ammonia levels will mess with the pH) then keep adding ammonia while you gradually adjust the pH to where you want it and then get fish.
Personally I would go with option 1, however if you have your heart set on a fish that won't like your water it's not impossible, it will just require a little hard work and patience.
Any good species information site should give you a pH and hardness range for the fish, a good place to start is our own species index compiled by forum members.
Now you can browse through the fish index's and start creating a shortlist based on the size and water requirements of the fish
Feeding Requirements
Unfortunately one of the most common mistakes made by fishkeepers is to assume that everyone can happily exist from flake food alone, poor nutrition is one of the common contributing factors to disease. Just like all other animals fish range from omniovers, piscevores and herbivores etc. Fish will also prefer to take they're food from different points in the tank, some feed from the surface, some mid water and some from the floor. Now if you have two species one a piscevore and one a herbivore and they both need to take food from the surface how are you going to ensure each species eats the food meant for them? Simple answer is that you can't. Now if you have bottom feeders who require vegetation and surface feeders who require meaty food it's OK to mix them, you'll be able to get the right food to them, for the most part it won't matter if they eat a little of the wrong food, the issue is making sure 80/90% of what they eat is suitable for them.
So once again, check the species index and google for feeding requirements and see who you can mix.
Swimming Levels
In a standard community tank it's nice to have a mix of swimming levels across the tank, this will also allow you to have more fish in the tank. If all the fish you like are bottom dwellers you may find the tank looks a bit bare in the middle and the fish are all crowded and don't have enough room to swim.
If you can then divide the fish up so you have roughly one third of the stocking given over to bottom, middle and top dwelling fish. This gives everyone plenty of room, means you won't have any bare areas in the tank and you can fill the tank to a decent capacity (which lets face it, most beginners want a nice full looking tank with plenty of variety).
Aggression and Territoriality
So you've hunted through the species index, you've got a list of possible fish and checked all the factors above and on that list are Oscars and Cories, your tanks big enough, they feed in different parts of the tank, they are both happy in your water and you've a nice mix across the tank. So what's the problem, yes your Cories will end up becoming an expensive snack for the Oscar
. OK so this is an extreme example but aggression and territoriality is very very important. Big aggressive fish and small peaceful fish do not mix well. There are basically 4 levels of aggression, IMHO it's best to pick one level of aggression and make sure al your fish are in it. If you have any aggressive fish at all you should know that any stocking combination is a risk and you should have a back up plan for re-homing some fish if need be. Don't let this put you off but you should just be aware of the risk
1 - peaceful - most tetras, danios, rasboras, cories etc will fit into this group, if all your fish do then you're OK
2 - mild-moderate aggression - fish like rams, gourami's and angelfish which can go in with more peaceful fish providing they are given ample room and their own territories
3 - aggressive fish - most medium-large cichlids, some larger catfish and plecs. Most of which can be mixed with each other given proper room and territories but who shouldn't be put with anything peaceful
4 - super aggressive fish - now these aren't nescessarily all big fish, siamese fighters and dwarf puffers would also come into this group but along with arowanas, large puffers fish and things like that. A lot of these fish need to be kept in species only tanks or by themselves, when you get into this sort of group you definatley need to check the individual fish's requirements in much more detail.
So you need to select fish with similar aggression levels, and make sure if anyone's aggressive that none of it's tankmates can fit in it's mouth!
With territorial fish you need to consider the decor of the tank carefully, they will most likely want their own cave or area of the tank so you need to make sure you have room for all of them.
Group Numbers
OK now you should have a list of compatible fish suitable for your tank, the next thing to work out is how many of each you need, most species will fit into one of the following groups
1 - single fish - species which can't be kept with others of they're own kind, you should only ever have 1 to a tank
2 - pairs - species that need to be kept in a m/f pairing so you need to learn how to tell males from females and get one of each
3 - trio/hareem - species that need more females than males (i don't know if this ever happens the other way around) most livebearers such as platies, guppies etc whould be kept with a minimum of 2 females to every male or the male will stress the females trying to breed with them all the time. Some species will require more than 2 females to every male.
4 - shoals - species that go for safety in numbers so need to be kept in groups of 6+
Total Number of Fish
As you should have learnt by now fish vary so much it's impossible to give a dead set rule for how many fish your tank can hold. The guideline that I use and is widley accepted is 1" of fish for every us gallon of water. So for example if your tank is 20 gallons, you can have 20" of fish in total.
So take your shortlist and find the maximum adult size of each fish, times this by how many of them you need to keep and add them all together. And guess what, it comes to more than you can have in your tank doesn't it? Well now comes the tricky part which I can't help you with much. You need to decide which ones you like best and what not to get.
Don't forget if your not sure then just post your stocking list and the size of your tank and we will help you out
So good luck with your research and I hope this helps you create a happy tank
One point I need to make clear before we start looking at the basic guidelines is that the requirements will differ from species to species, these rules will give you an initial idea of how to work out sensible stocking for your tank, once you've gone through the following steps and worked out a list post it up on the forum and we will give your our input and let you know if there's any problems.
Tank Size and size of fish
The first thing to think about is the size of your tank, I say this first as if you've already got the tank it's the one thing that can't be changed.
There are two factors to consider with the size of your tank, the dimensions and the total volumne.
Firstly you need to work out the biggest size fish you can have for your tank, here is a guide written by CFC one of our experienced moderators, it's written to apply to large catfish however I think the same basic rule applies. To work out the absolute minimum tank dimensions for most fish you find it's adult length the tank must be 4x this long and 1.5x this wide and tall, this gives turning room and swimming space. So for example if the fish you like is 3" long, the tank must be 12"x4.5"x4.5". Some species like angelfish need a really tall tank, some species like a lot of malawi cichlids like a long tank but aren't bothered by the height so the dimensions of the tank can be crucial.
You then need to take into account the total volume required for the fish, requirements will vary so look at the species index or just use google.
For some fish dimensions are more important, for some the water volume is more important. You should find out they're requirements for both if possible and take the larger number as the minimum tank size.
So you should now have an idea of the largest size fish you can put in your tank which will help you choose fish.
Water Requirements
Water Requirements mostly relates to the pH and hardness of water, all fish need to have 0 ammonia and nitrite and low nitrate levels. Here is a good topic explaining pH and hardness of your water.
The most important thing to remember with pH is stability is the key, most community tropicals will adapt to a pH slightly out of their comfort zone so don't panic if yours is a little higher/lower than ideal, it's better to leave it at that and have it stable than try and adjust it and have it fluctuating.
You have to make a choice at this point based on the pH and hardness of your tap water, you can either
1 - Choose fish to suit your water, so they will be happy and you won't have to try and change anything
or
2 - Change your water to suit the fish you like, bear in mind that adjusting pH is very tricky and ideally it should be done when the tank is cycled but with no fish in, so you would need to complete a fishless cycle (don't try and adjust it while cycling, the high ammonia levels will mess with the pH) then keep adding ammonia while you gradually adjust the pH to where you want it and then get fish.
Personally I would go with option 1, however if you have your heart set on a fish that won't like your water it's not impossible, it will just require a little hard work and patience.
Any good species information site should give you a pH and hardness range for the fish, a good place to start is our own species index compiled by forum members.
Now you can browse through the fish index's and start creating a shortlist based on the size and water requirements of the fish
Feeding Requirements
Unfortunately one of the most common mistakes made by fishkeepers is to assume that everyone can happily exist from flake food alone, poor nutrition is one of the common contributing factors to disease. Just like all other animals fish range from omniovers, piscevores and herbivores etc. Fish will also prefer to take they're food from different points in the tank, some feed from the surface, some mid water and some from the floor. Now if you have two species one a piscevore and one a herbivore and they both need to take food from the surface how are you going to ensure each species eats the food meant for them? Simple answer is that you can't. Now if you have bottom feeders who require vegetation and surface feeders who require meaty food it's OK to mix them, you'll be able to get the right food to them, for the most part it won't matter if they eat a little of the wrong food, the issue is making sure 80/90% of what they eat is suitable for them.
So once again, check the species index and google for feeding requirements and see who you can mix.
Swimming Levels
In a standard community tank it's nice to have a mix of swimming levels across the tank, this will also allow you to have more fish in the tank. If all the fish you like are bottom dwellers you may find the tank looks a bit bare in the middle and the fish are all crowded and don't have enough room to swim.
If you can then divide the fish up so you have roughly one third of the stocking given over to bottom, middle and top dwelling fish. This gives everyone plenty of room, means you won't have any bare areas in the tank and you can fill the tank to a decent capacity (which lets face it, most beginners want a nice full looking tank with plenty of variety).
Aggression and Territoriality
So you've hunted through the species index, you've got a list of possible fish and checked all the factors above and on that list are Oscars and Cories, your tanks big enough, they feed in different parts of the tank, they are both happy in your water and you've a nice mix across the tank. So what's the problem, yes your Cories will end up becoming an expensive snack for the Oscar
. OK so this is an extreme example but aggression and territoriality is very very important. Big aggressive fish and small peaceful fish do not mix well. There are basically 4 levels of aggression, IMHO it's best to pick one level of aggression and make sure al your fish are in it. If you have any aggressive fish at all you should know that any stocking combination is a risk and you should have a back up plan for re-homing some fish if need be. Don't let this put you off but you should just be aware of the risk1 - peaceful - most tetras, danios, rasboras, cories etc will fit into this group, if all your fish do then you're OK
2 - mild-moderate aggression - fish like rams, gourami's and angelfish which can go in with more peaceful fish providing they are given ample room and their own territories
3 - aggressive fish - most medium-large cichlids, some larger catfish and plecs. Most of which can be mixed with each other given proper room and territories but who shouldn't be put with anything peaceful
4 - super aggressive fish - now these aren't nescessarily all big fish, siamese fighters and dwarf puffers would also come into this group but along with arowanas, large puffers fish and things like that. A lot of these fish need to be kept in species only tanks or by themselves, when you get into this sort of group you definatley need to check the individual fish's requirements in much more detail.
So you need to select fish with similar aggression levels, and make sure if anyone's aggressive that none of it's tankmates can fit in it's mouth!
With territorial fish you need to consider the decor of the tank carefully, they will most likely want their own cave or area of the tank so you need to make sure you have room for all of them.
Group Numbers
OK now you should have a list of compatible fish suitable for your tank, the next thing to work out is how many of each you need, most species will fit into one of the following groups
1 - single fish - species which can't be kept with others of they're own kind, you should only ever have 1 to a tank
2 - pairs - species that need to be kept in a m/f pairing so you need to learn how to tell males from females and get one of each
3 - trio/hareem - species that need more females than males (i don't know if this ever happens the other way around) most livebearers such as platies, guppies etc whould be kept with a minimum of 2 females to every male or the male will stress the females trying to breed with them all the time. Some species will require more than 2 females to every male.
4 - shoals - species that go for safety in numbers so need to be kept in groups of 6+
Total Number of Fish
As you should have learnt by now fish vary so much it's impossible to give a dead set rule for how many fish your tank can hold. The guideline that I use and is widley accepted is 1" of fish for every us gallon of water. So for example if your tank is 20 gallons, you can have 20" of fish in total.
So take your shortlist and find the maximum adult size of each fish, times this by how many of them you need to keep and add them all together. And guess what, it comes to more than you can have in your tank doesn't it?
Well now comes the tricky part which I can't help you with much. You need to decide which ones you like best and what not to get. Don't forget if your not sure then just post your stocking list and the size of your tank and we will help you out
So good luck with your research and I hope this helps you create a happy tank
I am looking through my Complete Encyclopedia of Tropical Fish and the more I'm getting in to it the more confused I get...
