Minimum tank size question

[VioletEmber]

So I was doing research on black mollies and saw minimum tank size as 30g. It got me thinking because I see this sort of description a lot "fish's min tank size is 30 g. They do best I schools of 6 or more". ( not necessary mollies, but just what I see in a lot of profiles). So do they mean 6 in a 30 gallon would be ok, or just one?

I have seen it more explicitly laid out in terms of goldfish - 20g for one, add 10g for each additional fish... But what about guppies, neons, danios, etc. Seems like what they are saying in these profiles is the minimum ideal situation would be a school of 6 (or whatever) in the 30g (or whatever the min tank size is). But am I right?

It seems like they would be more explicit if what they meant was the min tank size for one is 30g but if you want a complete healthy school you actually need a 60g! Am I driving myself nuts here?

 

[GodFan]

It is confusing. Just figure this: If the fish is 4 inches or more (with some exceptions i. e. black kuhli loach) then you need a tank that is 10 times its size in gallons. This doesnt necessarily mean 1 4 inch fish in a 40 gallon. It means you need to start with a 40 gallon for swimming space. Then just think about the bioload and whether they school or not. So lets say a 4 inch rainbow fish ok? There bioload isnt extreme. So you need at least a 40 gallon tank but they school. So figure you need 6? A 40 gallon long tank should house 6 of said fish. So 40 gallon minimum would be for the school.
I know that sounds confusing lol here is a link to another thread about stocking. It outlines a new stocking calculation method: http://www.aquariumadvice.com/forums/f12/new-stocking-rule-186134.html

 

[NYgiantsRP]

Well Im not trying to come up with any rules or calculations, just common aquarium sense. With the mollies I would say 2 in a 10g is ok, 4 in a 20g 6 in a 30g and so on. Then just some small bottom dwellers, shrimp, or snails as tankmates.

 

[GodFan]

Well Im not trying to come up with any rules or calculations, just common aquarium sense. With the mollies I would say 2 in a 10g is ok, 4 in a 20g 6 in a 30g and so on. Then just some small bottom dwellers, shrimp, or snails as tankmates.

Respectfully I would like to disagree on 2 points. 1) I really believe you can keep more mollies than that in a 30 gallon tank. Good filtration, proper feeding, and water changes leaves plenty of room. 2) I really believe we need a new "rule". Something to help guide newbies better. Without a "rule" nobody will understand stocking and you will have newbies with 20 guppies in a 20 gallon tank because they are small.

 

[VioletEmber]

It is confusing. Just figure this: If the fish is 4 inches or more (with some exceptions i. e. black kuhli loach) then you need a tank that is 10 times its size in gallons. This doesnt necessarily mean 1 4 inch fish in a 40 gallon. It means you need to start with a 40 gallon for swimming space. Then just think about the bioload and whether they school or not. So lets say a 4 inch rainbow fish ok? There bioload isnt extreme. So you need at least a 40 gallon tank but they school. So figure you need 6? A 40 gallon long tank should house 6 of said fish. So 40 gallon minimum would be for the school.
I know that sounds confusing lol here is a link to another thread about stocking. It outlines a new stocking calculation method: http://www.aquariumadvice.com/forums/f12/new-stocking-rule-186134.html

Actually, it makes perfect sense! Lol... And the new stocking "rule" is definitely more accurate-- I got some zebra danios because i saw that a 20g was ok. It wasnt until I found this forum I found out what a 20 long even was! I was looking at one at the store the other day and it's a whole different tank and I completely get how different fish and plants would be better suited to it.

So yes, a tank that gives one fish enough freedom of movement would allow a certain number of additional fish the same freedom of movement. Up to a point! Thanks- this really helps!

 

[Mumma.of.two]

I'm sorry godfan but that is so flawed. Rainbow fish are active so even a 40g wouldn't suit. According to your 'Rule' a 12 inch Oscar needs a 120g tank. You can have a mated pair in a tank that size.
There are too many variables to make a rule that covers all fish and all tank sizes.

 

[aqua_chem]

There are many reasons that fish need tanks of a certain size, including water quality issues, size issues, and behavior. The fact of the matter is that fish are complicated organisms that will never fit to an 'entry level' rule that isn't convoluted to the point of unusability. Our best bet would be an online resource like aqadvisor that can be programmed with all the nuance, but even aqadvior is still in it's fledgling stages, and I wouldn't trust it to stock my tank any more than I would trust an 8 year old to drive my car. There is no replacement for copious amounts of research, at least not yet.


On a related note, I don't think Mollies are gregarious, so you don't necessarily need 6.

 

[GodFan]

I'm sorry godfan but that is so flawed. Rainbow fish are active so even a 40g wouldn't suit. According to your 'Rule' a 12 inch Oscar needs a 120g tank. You can have a mated pair in a tank that size.
There are too many variables to make a rule that covers all fish and all tank sizes.

ok I said a 40 gallon LONG. I have seen long 40s so I believe that is acurate. 120g, to my knowledge, would be suitable for an oscar. If you have an oscar you dont usually want a bunch of them. 120 gallons is huge. Most people dont have tanks bigger than that but I know people keep oscars. So obviously that tank is big enough. Unless I am misunderstanding you and you are saying it is to big? Either way I did say there would be exceptions. This is just meant to help.

 

[Mumma.of.two]

One Oscar can live in a 75g is what I'm getting at. By your rule one needs 120g. It just seems overly complicated and has so many exceptions for this reason or that. No rule will ever replace knowledge IMO.
It was a good idea but I don't see it working.

 

[absolutangel04]

Unfortunately, Violet Ember, there is a lot of dispute about the minimum tank sizes for any fish. I think that in general, quite a few people on this forum accept a similar size for certain fish, but then if you look at another forum you will find VERY different ideas. It is confusing. I agree.
Often, those tank sizes are listed for a group, but sometimes they are given as the minimum tank size for a juvenile, and sometimes its just for 1 adult fish.
For instance with mollies, I personally consider about 20g to be the minimum for that species to live to its potential (in size, years, and behavior). But, if somebody had a 17g tank and asked me if a molly was ok in it, I would probably say yes. If somebody had a 15g long, I would probably say yes. So, even though I just said that about 20g is the minimum, I contradicted myself because another tank was good too. The longer I am in this hobby, it seems to me more and more that the individual circumstances determine what fish would well in what tanks as long as the tank in question gives some fin room for a full-sized adult. So, that makes it even more confusing. Lol.
It seems to me that the best ting I personally can do is to offer my experiences and tell what I learned from them. But thats not vague at all, is it? Lol.

 

[GodFan]

I think something to base off helps but I do agree expierience is best. Unfortunatly we all start somewhere with zero expierience. Also I can't thik about stocking levels in an abstract way. I have to have something concrete (a rule) to base on. I dont live by it. I use it to help myself keep track of everything.

 

[maxwellag]

I agree, that the new "rule" is flawed... Tanks vary in shape. Why not use the length and width of the tank instead?

 

[GodFan]

I agree, that the new "rule" is flawed... Tanks vary in shape. Why not use the length and width of the tank instead?

I do. If you read the thread on it you can see it. I know the system can be confusing. I am going to use it myself though. I find myself using the inch per gallon thing to help keep track of stuff but I end up saying that this fish is worth 3 inches even though it is only 1 inch because of its bioload lol Now I can just say it is worth 3 points! lol

 

[maxwellag]

I do. If you read the thread on it you can see it. I know the system can be confusing. I am going to use it myself though. I find myself using the inch per gallon thing to help keep track of stuff but I end up saying that this fish is worth 3 inches even though it is only 1 inch because of its bioload lol Now I can just say it is worth 3 points! lol

I read the thread before... I think you should be more specific...for example, you could come up with a better equation like "the surface area of the tank divided by something equals inches of fish to stock." you could also factor in bioload some how, with the size of tank and filtration surface area and flow rate.

 

[GodFan]

I read the thread before... I think you should be more specific...for example, you could come up with a better equation like "the surface area of the tank divided by something equals inches of fish to stock." you could also factor in bioload some how, with the size of tank and filtration surface area and flow rate.

I asked for suggestions and nobody really added any!

 

[maxwellag]

I asked for suggestions and nobody really added any!

I did! LOL

 

[GodFan]

Oh I didnt see it... Sorry. Well get back on there and help me perfect! lol

 

[maxwellag]

Oh I didnt see it... Sorry. Well get back on there and help me perfect! lol

LOL I will when I have some free time to type a really long reply.

 

[bruinsbro1997]

Mollies need a 20 Gal Tank minimum. You can't even use fish length as one variable. Take into consideration the bioload of a mollie. They poop a lot and are messy eaters. With proper filtration I think it is feasible to keep one in a 20 Gal tank. You can't make a rule. There's too many variables to be taken into account.

Minimum tank size depends on a variety of things. Usually I avoid those on the Internet and just ask the people here.

 

[GodFan]

Mollies need a 20 Gal Tank minimum. You can't even use fish length as one variable. Take into consideration the bioload of a mollie. They poop a lot and are messy eaters. With proper filtration I think it is feasible to keep one in a 20 Gal tank. You can't make a rule. There's too many variables to be taken into account.

Minimum tank size depends on a variety of things. Usually I avoid those on the Internet and just ask the people here.

Did you even read it? Because it isnt the inch per gallon rule.