Amount of fish per tank

[MysterioMask]

I have been reading different things about rules for fish per gallon. It seems many people say about 1 inches of fish for about every 3-5 gallons. Many say it's because of the bioload .My question is that let's say you have a 30 gal tank and a 30 gal sump tank. Do you now have 60 gallons to add fish or is it still only 30 gallons?

 

[reeferfoxx]

I have been reading different things about rules for fish per gallon. It seems many people say about 1 inches of fish for about every 3-5 gallons. Many say it's because of the bioload .My question is that let's say you have a 30 gal tank and a 30 gal sump tank. Do you now have 60 gallons to add fish or is it still only 30 gallons?

It's an old rule. Husbandry and maintenance can allow X amount of fish. Now a good number is also dependent on what type of fish and the footprint or dimensions of the tank. Since you only have roughly 15 gallons of water in a 30 gallon sump, that would put you at 45 gallons. But if it were my tank, I would stop at 4 fish and see how things go for a bit then work on 5 and maybe 6.

 

[sbash]

The sump does not play a part in the amount of fish game. Unless you are putting fish in it... What really matters is the area the fish can swim.

In your 29 gallon, you are more limited by the type of fish you can keep (i.e. their compatibility), which will ultimately limit your numbers.

 

[eatbreakfast]

Total system volume does affect fish keeping capacity, but so does the space for the display.

Having a sump increases surface area for gas exchange. O2 levels are one factor in stocking capacity, so more surface area and overall volume equal a more stable O2 level.

Having a sump also increases surface area for beneficial biological activities. It also allows for more effective mechanical and chemical filtration. It also serves as a refugium for amphipods and copepods, even if not setup as a refugium.

However, diaplay tank dimensions can still be a limiting factor regardless of sump volume, as size of the fish, swimming activity, territoriality, and aggression all factor into stocking capacity.

Ultimately, add fish slowly, test water and observe behavior often. If your system can adequately handle the bioload and there isn't aggression, then you haven't reached capacity. Simply stated, there can't be a hard and fast rule of thumb for stocking because there are too many variables at play.

 

[4FordFamily]

Total system volume does affect fish keeping capacity, but so does the space for the display.

Having a sump increases surface area for gas exchange. O2 levels are one factor in stocking capacity, so more surface area and overall volume equal a more stable O2 level.

Having a sump also increases surface area for beneficial biological activities. It also allows for more effective mechanical and chemical filtration. It also serves as a refugium for amphipods and copepods, even if not setup as a refugium.

However, diaplay tank dimensions can still be a limiting factor regardless of sump volume, as size of the fish, swimming activity, territoriality, and aggression all factor into stocking capacity.

Ultimately, add fish slowly, test water and observe behavior often. If your system can adequately handle the bioload and there isn't aggression, then you haven't reached capacity. Simply stated, there can't be a hard and fast rule of thumb for stocking because there are too many variables at play.

Agree.

Nutrient export is critical component as well, the type of fish (tangs, puffers, most predators for instance are dirty and have high bioload effects), fish size, husbandry (water change frequency for instance), and tank maturity are relevant as well.

 

[5altkreep]

Great advice so far. My recommendation would be to forget about old "rules" like that. Do some research and planning. Get together a list of fish you would like to keep. Post your list here and we can help you determine which fish will play nice together, and what order to add them.
Good luck!

 

[HB AL]

As many as you can keep alive with your current setup.

 

[TbyZ]

I have been reading different things about rules for fish per gallon. It seems many people say about 1 inches of fish for about every 3-5 gallons. Many say it's because of the bioload .My question is that let's say you have a 30 gal tank and a 30 gal sump tank. Do you now have 60 gallons to add fish or is it still only 30 gallons?

My rules are -
1. if your filter can handle the load,

&

2. they all have their own nice place to sleep when the lights go out, you haven't got too many.

 

[MysterioMask]

So basically what I'm hearing is start with 2 or 3 fish and see how things go. Add more later if all is well.

My current plan is to keep mostly peaceful passive and small fish .

 

[HB AL]

I would say to keep whatever fish you like and are interested in, I wouldn't start putting fish in just because they are considered peaceful unless it happens to be one you like. There is a fine line on how many fish you can keep but your systems size and bio load capability will determine that. I have sixteen fish in my 92gal system with some of them getting to be a good size but they all get along and the reef has no problem sustaining them, I have lots of corals many of them acros with no ill affects from what some would consider a very "overstocked " tank.