how many fish?

[person]

hello i have a fish tank and would like to know if there is any good rule of thumb for how many fish i could fit per gallon or something like that. thank you in advance.

 

[fishski13]

There really isnt a general rule of thumb for fish stocking because every tank and fish is different. Some fish that are 5 inches need different space than other fish that are 5 inches. It all depends on what fish you have, your current stocking of fish and coral, and size of tank that can help determine if a fish is a good fit to a tank.

 

[Rmckoy]

There used to be a guide suggesting 1” of fish per 10 gal free swimming space .
but it’s obviously not even close to accurate .
Depending on biological limitations . You will know if you over stock too fast .
ammonia will spike and most likely kill every fish .
Stock slow and keep a eye on ammonia and other nutrient levels.

 

[Rmckoy]

There used to be a guide suggesting 1” of fish per 10 gal free swimming space .
but it’s obviously not even close to accurate .
Depending on biological limitations . You will know if you over stock too fast .
ammonia will spike and most likely kill every fish .
Stock slow and keep a eye on ammonia and other nutrient levels.

This said I still wouldn’t put a 2” long tang in a 20 gal some of this has to be put on the owners to provide proper care .

 

[Anemone_Fanatic]

Unfortunately, there isn't a simple rule to determine stocking density. Many people will suggest the "inch per gallon rule", but that doesn't account adequately for the square cube law and the total biomass of a fish. Other factors include flow, feeding, aquascape, nutrient export, the behavior of the fish species, etc. How big is your tank, and what filtration do you have?

 

[person]

oh, i see thanks for all of your help. i appreciate it.

 

[TheoneandonlyME]

As everyone said, there isnt a rule of thumb BUT if we get the size of the tank we can help. For a 10 gallon, a clown would work. Make sure its ocellaris. You could also add a firefish but they tend to hide a bit. For 20, a pair of clowns would do. Maybe a royal gramma and clownfish also. 30, flame hawkfish, clown, bengai or pyjama cardinal pair and a royal gramma or firefish. (You could tell i love clowns). Remember, im very new to the hobby so always check in with someone more experienced. Btw, 10 is 10 gallons, 20 is 20 gallons and 30 is 30 gallons. And the fish i mentioned are all reef safe

 

[Jekyl]

Tank size, age, amount of rock and temperament of fish all come into play

 

[TheoneandonlyME]

True, but its just a rough estimate of a few tank sizes.

 

[i cant think]

hello i have a fish tank and would like to know if there is any good rule of thumb for how many fish i could fit per gallon or something like that. thank you in advance.

If you have an FTS of the tank as well as in tank dimensions we can give you a rough estimate.

 

[i cant think]

Duplicate

 

[i cant think]

Duplicate

 

[PatW]

Any rule of thumb is pretty sloppy.

A person with a tank with excellent husbandry: automatic water changes, filter socks, skimmer, chaeto refugium, aeration, temp control, ATO and decent flow, will be able to have far more fish per gallon then a tank that is just a tank with no husbandry.

Another thing, even with the best husbandry in existence, things will not work if you have even a small fish that is hyper aggressive and dedicated to the proposition of murdering all of its neighbors. The community you have makes a big difference.

And an inch of fish is not a good rule. A fire fish is about 2” - 3” but they are very slender, sedentary, passive so they do not add much stress to the system. My kole tang eats piles of nori, is very active and full bodied but it is maybe twice as long as a fire fish, but I bet it has 10 times the impact.

Also, it you are in an area with possible long power interruptions those can cause a tank crash if you have a system with a bunch of fish because all of your systems will shut down (unless you have a power back up). My system has been through multiple power shut downs of pretty long duration (say 5 days) but with battery powered aeration it has come through. So plan for a worse case.

 

[nereefpat]

It's best to start with tank size and listing what fish you might like to keep.

 

[TheSheff]

Fish tank stocking is different for every tank and can depend on a variety of factors like age of the tank, methods of filtration, reactors etc. I have a 15 gallon tank that has a very high bio load but I just run GFO and use a protein skimmer at all times.

 

[EeyoreIsMySpiritAnimal]

hello i have a fish tank and would like to know if there is any good rule of thumb for how many fish i could fit per gallon or something like that. thank you in advance.

Short answer is: No.
Your best bet is to make a list of the fish you want, then research the needs of each fish. Also research their temperament and compatibility with the other fish on your list.

It sounds like you're new to the hobby. There are a lot of good resources on this site... Go to the sticky threads at the top of the various forums and read as much as you can before buying any livestock.

Good luck!

 

[EeyoreIsMySpiritAnimal]

Fish tank stocking is different for every tank and can depend on a variety of factors like age of the tank, methods of filtration, reactors etc. I have a 15 gallon tank that has a very high bio load but I just run GFO and use a protein skimmer at all times.

Bio load is only one factor. An active fish needs much more space than a less active one, regardless of how much waste they produce.

 

[TheSheff]

I agree, size and activity level are definitely important but people set standards like 1 gallon per inch of fish or whatever i t is and I don't always agree with just simply going off of that.