Stocking Fish- To Calculate or Not to Calculate

[LittleParr]

How much should you stick to the calculators when determning how many fish you can put in your tank? Having just 6" of fish for a 33g means you wouldn't even be able to keep two perc clowns! (Fosters and Smith say their adult length is 4").

 

[Hara]

The calculation tools are just a rule of thumb. Different types of fish affect bioload in different amounts. An example would be that puffers, triggers, lions and eels are pretty heavy on the bioload where as similar sized fish such as tangs, angels and butterlies are not. Calculators are guidelines used to steer you in the appropriate direction and help you think.

 

[Raker333]

In the end I will keep 3 chromis and 2 clowns in my 29gal.

 

[tecwzrd]

You forgot to “minus the tail”.

For beginner SW aquarists the general rule of in/gal in saltwater should be followed closely to alleviate fish stress/water quality issues IMO and if you don’t have the space for your fish when they are adults then you are just asking for trouble down the road. Especially with predator fish which can be excessively messy.

Experienced fish keepers can exceed the rule slightly mostly because they often have the proper equipment for keeping the water quality high ie: 1+ lbs of lr per gal, quality skimmer, dedicated water changes with ro\di water, & frequent testing to ensure their results are working.

I still think fishfreek said it best though.

My definition of overstocked is very simple.

If all your pumps fail for a period of 12 or more hours will your fish sufficate due to lack of oxygen? If so your overstocked no mater how well your water conditions are when all your equipment is running. If your pumps work than they can live with out issues but if your pumps fail for a period of a few hours you will have deaths.

 

[LittleParr]

How much do inverts affect the bioload... like if you have alot of crabs, shrimp, and snails should you have less fish?

 

[tecwzrd]

How much do inverts affect the bioload

Almost none and should not be considered for the most part in the “calculations”

 

[LittleParr]

when considering the adult size of the fish, how do you minus the tail?

 

[tecwzrd]

Good question I feel most tails take up about 20% of total size of the fish. So if you are looking at 15” of fish for a 75 gal then realistically adding 20% to that total would give you 18” of fish.

The calculator follows the 1” per 5 gal rule pretty closely but if you minus the tail then its closer to 1” equals 4.15 gal. Really I have no idea why they just don’t use that formula and get rid of the somewhat confusing statement “minus the tail”

 

[localhost]

Clarify this, I assume the gallons is water volume, not tank size. A 55G tank with 75#'s of LR will probably only hold 40-45 Gallons of water. So using a 1"/5G rule, would you only be allowed 8-9" of fish? I think this is what is meant, correct?

 

[tecwzrd]

It states “Size of tank in US gallons” so I would have to assume a 55 gal tank is still a 55 gal tank even if it only holds 40+ gal due to lr. I’ve seen other sites give 1” per 4 gal for fish/inverts and even up to 1” per 2 gal for FO. IMO 27.5” of fish in a 55 gal SW FO would be heavily overstocked.

FWIW all fish calculators are just a basic rule of thumb that the aquarist should follow as closely as possible to avoid overstocking. Ultimately it’s up to each individual to properly care for their fish/inverts.