1" per gallon rule?

Question

Ok, I've been getting mixed information, on this. Typically I've been told for my tropical fish 1" of fish for every gallon is recommended. Do I count my bottom feeders, and frogs in this?

Answer 1

Rather than "Rules" these should be thought of as "Suggestions". Everyone has different ideas and different methods of calculating bioload. The "inch of fish per gallon" is a simple guideline, but doesn't take into account body shape - fish with wide or deep bodies produce more wastes than fish with thin, slender bodies. Another guideline uses grams of fish per liter of water - this will take body shape into consideration because a "wider" or "taller" fish will have more weight from the additional body mass (but have you ever tried to weigh a fish?). There's also an inches of fish (okay, we already know the problem here) per surface area - multiply the length and width of your tank and divide this number by 12 for the "inches" of fish to keep - this is the only method that takes into consideration the shape of the tank and the O2/CO2 exchange. None of the methods considers space needs based on activity level or territoriality.

None of these methods will mean anything if you overfeed or don't perform water changes on a regular basis. You can get away with higher stocking rates with larger filters and/or using a sump (hidden tank plumbed to your fish tank to increase your overall water volume (this is what fish stores use, which is why they look overstocked, plus they usually have an automatic water replacement system that changes a set volume per hour) Maybe the best thing to do is calculate using several methods and take an average, or consider your committment and experience in fishkeeping (or lack thereof) and keep the stocking at the lower end of the range - this would be the safest method.

Yes, you will need to consider bottom feeders and frogs in your stocking.

Answer 2

Consider the rule as more of a beginners guide. It works quite well for the common, small sized community fish. Once you gain experience you'll realize the rule is inaccurate and unnecessary, but it's safe until then.

You can't use the rule:

With big fish. As already mentioned by a poster, imagine a 12 inch Oscar in a 12 gallon tank - the poor thing couldn't move and would quickly die of water issues. As fish get longer they also tend to get taller and thicker. They use much more oxygen and create much more waste.

With territorial fish. Many fish will declare a portion, or all, of a tank as it's own territory. This is very common with cichlids, and can also be seen in freshwater 'sharks', some pleco's and catfish, and others. Two kribensis will take over an entire 10 gallon tank, yet they only grow to a couple of inches long.

And in fact, some fish are quite opposite. Mbuna, for example, are generally stocked at quite a bit more then 1" per gallon - combining a large tank, lots of hiding spots, and crowded conditions, aggression that might otherwise be fatal to a lesser stocked tank becomes dispersed and harmless.

In the end the best rule of all is common sense and experience. How heavy you can stock depends much on your filtration and maintenance routine. Keep an eye on your nitrates, they are a good indication of how much more or less you can or should stock your tank. Also make sure you learn about the species of fish you are keeping. Do they grow big? Are they territorial? Should they be in schools? Are they sensitive to water conditions?

And last, don't ever go by the fish store. They severely overstock their tanks. They do water changes every day. They also, whether you like to believe it or not, lose many fish, much, much more then a typical aquarist would be comfortable with if they lost that many. Fish stores show tanks are temperary setups and likewise should not be used as examples. When in doubt, ignore the store.

Answer 3

This "rule" is such a general guideline it really should go away, but like so many disinformation items it just won't die. You really have to know the fish to know how many of what will fit in a tank. Example: a 10" Oscar will not go in a 10 gallon tank. 3 - 3" convicts will not live in a 10 gallon tank either. It is so very dependent on the activity level, bio load level and territorial nature of the fish that many, many fish do not apply to this rule. So many in fact that the rule is truly and honestly broken. Further more, how much bio load a tank can handle is heavily dependent on your filtration. Better filtration means more bio capacity.

Every living thing in a tank counts as bio load, so for this rule, yes frogs and bottom feeders count. But I would caution you against ever applying this rule and thinking it will work out well.

Hope this helps

MM

Answer 4

Yes. snails count too, as they produce waste also. You are correct as to mixed information! I too was also taught that for a freshwater, it is an inch per gallon ( of course there are exceptions and I won't go into those) but I have heard other people say it differently. After more than 16 years of fishkeeping, years spent working in pet stores, etc I have found that HARD and FAST rules are few. There are more guidelines that people call rules, and there are also exceptions/ Just as there are guidelines for which fish can go with what, I have seen fish get along that technically "shouldn't" and I have seen fish that are supposed to be peaceful be MEAN and aggressive.
So, my answer is, you have the guideline correct and any living creature that eats and produces waste counts towards your total. HTH

Answer 5

I have a 10 gallon tank and I have a huge goldfish one huge sucker fish and like 8 other fish....I kind of don't follow that rule because look at pet stores with like 20 fish in a 10 gallon tank...I say just make sure you are getting fish that have the same tempermant..... frogs and ghost shrimp really wouldn't count if you want to follow the rules but bottom feeders yes.

Answer 6

That takes guts to admit you'd buy a car like that. Good for you. Anyway, Suzuki has moved on and that 1.0L inline three cylinder is a thing of the past. Since consumers want power AND MPGs and the gubmint regulates all those airbags into cars now, cars tend to get heavier. That means if you want 50 MPGs, you have to pay for it now. Either with a diesel VW car or something akin to a hybrid. Newer Corollas and Civics are at least as big as 90s era Camrys and Accords. What can you do about progress?

Answer 7

I heard 1/2 inch of fish per every gallon from my local petstore. IF you have had your tank set up for about 6 months or so, you could put more in if its been established long enough, but only like 2 or maybe 3.

Answer 8

the entire rule isnt so great. Think you have a 20" in 20 gallon tank, does he have enough room to be happy? NO.


but if you beleive in that rul yes bottom dwellers and frogs would count they take up room too!

Answer 9

Yes you need to count them because if you get a huge bottom feeder its going to need more space than a small one

Answer 10

i always count bottom feeders, but i don't know about frogs. seems to me that i would count them as a gallon too. but i really don't know. but that is how i would do it, unless they are gargantuan frogs.