fish length

[thanew]

i understand that for one gallon of water you can have one inch of fish.. so for 55gallons you can have ~55 inches of fish or so...

but my question is how do I know when a fish is too big for the current aquarium -- I notice a lot of overcrowding in fishstores (thats to be expected I guess and I can't really get a straight answer out of them) where fish can barely swim in a straight line. I mean would I have to notice signs of stress? Would I have to notice that he can't turn? Or would it just be totally dependent on the fish itself?

Sorry if this is a bit of a newbie question..

-thane

 

[FishDaddy]

For the reason I would expect and have been told they do that is because the fish they get they usually sell pretty quick and they won't be staying in there that long.

 

[Jchillin]

thane - this is just a basic formula. It really depends on the types of fish a person is keeping. Some fish (active and/or agressive) need more room. Some fish grow to immense proportions and will outgrow a tank sooner or later. The idea is you should have no more than 1" per gal. due to bio-loads. LFS don't really adhere to this rule and most of their tanks are overstocked (50+ goldfish in a 30/40 gal tank). They believe they will sell these fish and this is why you often see dead fish in their tanks.

 

[gheitman]

LFS will also provide additional filtration to take care of the additional bio load. Just because you see twenty fish in a 10g tank at a store that doesn't mean it is recommended. The species of fish, the frequency you do water changes, the amount of filtration and whether your tank is planted or not all have an impact on how many fish you can have in a tank.

 

[BASSNMAN]

Fish stores don't go by the rules. The fish are there for only a short time. The inch per gallon rule has to be looked at with discretion. You could probably get by with 10 1 inch fish in a 10 gallon tank, but not 1 10 inch fish.

 

[thanew]

ok.. i understand the fishstore thing now, maybe I just go to some shady fishstores?

anyways back to the real question at hand.. what is the max length for one fish in one tank.. I know you can't put the 10 inch fish in a 10g tank, but does anyone have any info on this? I have a semi-large pleco 9-10 inches in my 55gal he seems to get along nicely in there and likes it but I want to know when it would be time to move him to a larger tank

 

[QTOFFER]

You already seem to know that the 1 inch per gallon rule goes out the window when large fish, like your common plec are concerned.

I've read that when the fish' length exceeds the shortest dimension of the tank, it has outgrown the tank. I think the idea is that the fish would have a hard time turning itself around if it was longer than the tank's back-to-front depth. Obviously, this is a bigger issue for large, active swimmers like oscars and pacus.

However, plecs are more-or-less sedentary, so I think the bottom surface area is more important than the tank dimensions. I'd say that one common plec should be able to happily live out its entire life in a 55 gal. Two plecs would probably appreciate the increased bottom surface area of a 75 gal.