what is the limit on the number of fish you can keep in a tank

[ColeMan]

Originally Posted by rasetsu

If you want to take this hobby seriously and give the best care for your fish, you are on the right track by posting on here. You have to learn to accept people's advice though. There are a lot of folks here who have kept many different kinds of fish for many years and know what they are talking about. My advice is to get a bigger tank with appropriate tank mates or get smaller fish.

couldn't have said it better myself...though I might add to the original poster that noone is trying to lecture you, as you mentioned in your earlier post, but rather simply trying to answer your question in the best way possible. my recommendation is that you heed the advice of the many intelligent people taking the time to answer your questions...

[plantbrain]

If you think about this question in general, how many fish can we add to a tank, it's really a good question.

What might it depend on?

filtration/flow
Water changes
Species of fish
Food, feeding frequency and type
Plant density/growth rates

I have a 20 gallon,
250 GPH
110w
CO2, dense planting
1-2x a week 60% water change
feed 2-3x a day, worms and flake

15 coral ark pencil fish
42 Cardinals
18 cory panda
30Amano shrimp
At least 20 cherry shrimp
15 Blue shrimp
6 clown Killis
And recently added 16 King emperor tetras.

I'll remove the King's, that adds a bit too much

But the tank has been running well for months and I just recently added the kings.

That's a pretty heavy bioload.
But it's well cared for and the fish are small, and yes, EI dosing routines+ ADA AS.

Regards,
Tom Barr

[James From Cali]

Tom, the other thing you have to look at is how comfrotable the fish are going to be. 42 Cardinal Tetras must be crammed in that tank. Although I do aggree that the more care you put into the tank the more you can bend the rules. With my 10g I am going to keep about 10 Long Finned Gold Zebra Danio and 10 Zebra Danio.

I honestly follow really no rules in this hobby. Yes I provide CO2 and nutrients to a limit. But I test things out and see what works for me(Higher light plants in lower light conditions) and I use the feedback sch as "Everything is going to die" and put it to the test. If you think about it how did they even come up with the "inch per gallon rule"? They must have tested it somehow. So if they had came up with a rule that shouldnt really even be followed who is to say you cannot find a loop hole for that rule.

I have not gone by the rules for many tanks so far. My neighbors 55g cichlid tank has Mbuna and a male Kribensis. Sure it is said not to do it but it has not been a problem. Trial and error my friends, trial and error. Test things out, do not be afraid to experiment, but do it within reason. Especially with our fishy friends.

[eyebeatbadgers]

Quite a lively tank eh Tom ?

[rasetsu]

Originally Posted by plantbrain

I have a 20 gallon,

15 coral ark pencil fish
42 Cardinals
18 cory panda

[lauraleellbp]

He's also doing 60% PWC 2x/wk, the stock are COMPATIBLE with each other both in terms of behavior and husbandry needs, and you can be sure all those plants are extremely healthy- BIG difference from your average hobbyist!

You could easily keep 100 cardinals in a 20gal tank given the water parameters are kept up; cardinals are one FW fish that are actually MORE happy in crowded conditions; wild schools often number in the thousands or more. Cories also are happier in bigger schools.

[rasetsu]

Originally Posted by lauraleellbp

He's also doing 60% PWC 2x/wk, the stock are COMPATIBLE with each other both in terms of behavior and husbandry needs, and you can be sure all those plants are extremely healthy- BIG difference from your average hobbyist!

You could easily keep 100 cardinals in a 20gal tank given the water parameters are kept up; cardinals are one FW fish that are actually MORE happy in crowded conditions; wild schools often number in the thousands or more. Cories also are happier in bigger schools.

So that's actually more like a 140+ gallon tank in terms of water quality. Definetly beyond average.

[TheXman]

Clown loaches grow so slowly, you might not notice too much growth, but add to that the facts that this one is in a small tank AND all alone (which does stress clown loaches), he's probably not growing or just growing very slowly because he is not thriving. The boesemani is acting like a jerk because he doesn't have any rainbow babes to show off to, or any rival males to try and show-up. Get a group of six or more in a tank that is 55 gallons or more, and you'll see the rainbows keeping themselves so busy, they don't bother with any of the other fish. I've got 18 rainbows, three different species, some as big as 4 inches, and they have never attacked my neon tetras, zebra danios, or lyretail killifish that are in the same tank. I'm not going to judge because the store that sold you these fish probably said they would be fine in your tank (they rarely will tell you that a fish gets too big for your tank), but take what everyone here is saying about the fish you stock seriously because they're giving you good advice that comes from a lot of experience. And definitely do some research on these fish, just keep in mind that maximum fish sizes are often gross underestimates, but rarely overestimates. You will find lots of sites that estimate the max size of boesemanis at 3 inches, sometimes smaller. Very few estimate the max size to be 6 inches, yet this is the true max size for this fish. Same goes for tank recommendations, the larger recommendations will be the more accurate ones.

[plantbrain]

Well, there's a point when you use lots of fast growing plants, have good trimming, well run bio filter, good current etc.

There's a lot of cover for the fish.

But it's not the final home for these fish.

I'm a strong advocate of reasonable homes for the entire life of the fish and if not, then generally as a test case.

Ultimately, I have a plan for any fish I might buy for my tanks.
But it's nice to test things out and see.

Ghost shrimp are excellent model critters, they are cheap and can be added slowly and progressively to see how far you can push a tank with bioloading.

I had about 250 when I manged the crash a tank and get GW algae.
There was lower plant biomass than my tank today however, about 40-50% less.

I care less about losing a few ghost shrimp at 10 cent each vs a cardinal, human judgment, but I really never wanted to keep 250 ghost shrimp either, it was more of a test to see what aspects under high light+CO2+ high fish loading would cause algae and if so, which types and how long.

Regards,
Tom Barr

[lauraleellbp]

Were those 250 ghost shrimp in a 20gal?