Fish Inches

[rfisher]

Hi All,

I have just discovered that with a 27.5 UK gallon tank I can have 55 Fish Inches. Does this mean that if I purchase fish that are 1" long I can have 55 of them?

Have I got this right?

Rich

 

[babybell911]

Well its a full grown rule. You have to consider the full grown length say a corydora can get to 2-3 inches but yeah if you get fish that max growth is an inch 55 fish it is but where would be the fun in that! But i think it's 1 inch of fishto each gallon so your more likely to be allowed 28 inches of fish

 

[Tokis-Phoenix]

Hi All,

I have just discovered that with a 27.5 UK gallon tank I can have 55 Fish Inches. Does this mean that if I purchase fish that are 1" long I can have 55 of them?

Have I got this right?

Rich

The rule is called the "one inch of fish per gallon" rule, but this is only a rule of thumb and not a proper rule, as it has many faults with it. In general though, 55 1inch fish would overstock your tank seriously. Secondly, the rule only applies to the length the fish will grow to and not their current size, so if you have 55 1inch common plecs the tank would be massively overstocked.
There are many factors to take into consideration when stocking a tank apart from just the size of the fish- activity levels, waste production, social requirements, habitat requirements, agression levels etc etc all need to be taken into consideration as well .

 

[dwarfgourami]

among the "many other factors" mentioned are the following:

the rule is only meant to apply to slim-bodied small fish, the kind of fish that grow to 3-4 inches max. For larger fatter fish or fish that are heavy poopers (like plecs) different rules apply
(basically, you can keep fewer and/or with extra filtration. It stands to reason that a 20 inch oscar has a lot more body mass than 20 neons, and is going to produce a lot more waste

it applies to tropicals only (coldwater fish need more oxygen, so more space)

some fish are highly territorial, so you may only be able to keep one of the same kind in the same tank

some fish needs lots of swimming space- it would be cruel to keep a 2 inch danio in a 2 gallon tank

in fact, the only fish you can keep in under 5 gallons is a betta

lots of fish are schooling, so you need to find the room for a whole school- or don't buy that species at all

other fish need special sex ratios

some fish have such special requirements that you may not be able to fit them in your tank

the rule is usually understood to be 1 fish inch/US gallon (3.8 ltrs/US gallon as opposed to 4.5 ltrs/UK gallon)

if the tank is very high=has little surface area, there may not be enough oxygen for that many fish even if filtration is adequate

 

[rfisher]

Hi,

Thanks all. That has made it a lot easier to understand now.

Rich