General Rule Of Thumb

Is there a general rule for number of fish per X gallons?

 

fresh or salt?
fresh is 1inch per gallon usually.
salt is generally one half or one third that(for reefs).
so 1 inch per 2 or 3 gallons.

this rule is incrediably foulible, depending on the size(diameter wise) of fish, and type of food the animals eat.

 

To the right of this page under 3 reef navigation is a calculator that can help you with that....


but I made it easy for you click here.....

http://www.3reef.com/aquarium_calculators/

 

That's awesome, I bookmarked it. Thanks!

 

This is a tricky one because there are sooooo many variables. The starting point is a max of one inch of fish per three gallons. Can you keep more? Yes. Is it wise? IMO no. The problem isn't so much waste as oxygen saturation. Great skimming, carbon and phosphate reactors, denitrators and refugiums have paved the way for nice, clean and healthy tanks. But oxygen saturation....that sets the true limit.

So we can start out stating that one inch per three gallons is the limit. Then we take into account the type of fish, the body size of the fish, the activity level of the fish, etc. You can make more oxygen available by lowering the SG a bit. 1.021 will give you better O2 sat compared to 1.028. Keeping air stones in the sump. Keeping your skimmer in good working order. Making sure that the surface water movement is good. If you have a sump/fuge, a 20g long is better than a 15g tall because of the additional surface area for gas exchange. One of the greatest inhibitors of O2 sat is the dreaded glass top. Not only does O2 drop, but CO2 levels increase. That results in carbonic acid formation and a drop in pH. But that is another discussion. Glass tops are not my favorite. Canopies are fine. Eggcrate or screens are fine.

Keeping a mellow environment (location of the fish tank) lowers the metabolism of the livestock by keeping them mellow yellow. A fish that is startled all the time will use up more oxygen at a faster rate.

It's just a lot of little things put together. My dream stocking level is one inch per five gallons. That gives me room for corals, inverts, this, that and the other thing. Right now, I am happy with my population, which is at one inch per four gallons.

The numbers to look for are the following. Saltwater has a base oxygen saturation of 6ppm. Fish are OK with levels down to 3ppm. Anything lower than that will put stress on the little fishies and they will die off one by one until the O2 sat is above the minimum and they are able to breathe.

Oops, I rambled again. Imagine that. Later gator and Peace.......John. ;D

 

This is all really great and much needed information. Thanks!