How many fish should i have? Newbie Question - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 7 Old 04-01-2009, 03:07 AM Thread Starter
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Dylan's Avatar
How many fish should i have? Newbie Question

Hello all, i have recently brought myself a 85 gallon fish tank (321 Liters). At this moment my fish tank consists of
1 Clown Loach
1 Bristlenose Catfish
1 Silver Shark
1 Rainbow Shark
1 Bronze Catfish
2 Chinese Algae Eater's
4 Swordtails
7 Tiger Barbs

I have been reading up on how many fish my tank should have and think this may be to many. I was hoping on adding some guppy's and possibly another Bristlenose and Clown Loach but now think i shouldnt.If any1 has any opinion on this i would really like to hear it thanks.
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post #2 of 7 Old 04-01-2009, 03:27 PM
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The more clown loaches you put in, the happier they will be.

Cause your friends are my friends, and my friends are your....anyway. Stupid song got stuck in my head...

My wife rolls her eyes when I talk about getting another tank
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post #3 of 7 Old 04-01-2009, 03:55 PM
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From What I have read through the years you don't want more than 1 fish per gallon!
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post #4 of 7 Old 04-01-2009, 04:40 PM
Don't ever listen to the fish per gallon rule. That's like saying you can put 10 Oscars in a 10G tank.
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post #5 of 7 Old 04-01-2009, 06:10 PM
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Cody's comment is important. The number of fish you can have in any tank is dependant upon several factors, some more important than others but all necessary.

The major issue is bioload, which is the effect each fish has on the environment in a closed system, that is, how much waste does it produce (through respiration and excrement) which interacts with the biological processes; and you must think ahead to the fullgrown adult size (unless you intend on giving them away before then). The bacteria have to be in sufficient population to handle the biolode from fish, invertebrates and plants.

A second thing that must be in balance with the stocking level is your tank maintenance (and here I include the weekly water changes and the filtration system). If the bacteria are adequate for the bioload, the ammonia converts to nitrite which converts to nitrate; plants can use some of the nitrate, and the rest you remove with partial water changes. Nitrate is also toxic at high levels (as can occur with a greater density of fish) and anaerobic bacteria in the filter and the substrate will break up nitrates to obtain oxygen, creating nitrogen gas in the process. Water changes are extremely important in any aquarium, but even more so the more and larger the fish.

Thirdly are the water parameters; if the pH and hardness and temperature are the optimum (best) for the particular fish in the tank, they will have much less stress and be less susceptible to other factors that would otherwise cause trouble.

Fourthly are plants; a planted tank has a somewhat greater capacity (providing the plants are growing healthy of course and not dwindling away adding to the bioload themselves) because they are nature's "filters" in the aquarium.

Each of these aspects must be balanced and in sync to avoid problems. At this point I should also say that the experience of the fishkeeper has a lot to do with it. Things can go wrong for all of us, and when it does, you have to be ready with the knowledge to rectify the problem or lose your fish. I remember my first 5g aquarium when I was in my teens (a long time ago, I assure you!) and how many fish I lost because I didn't know what I was doing and in those days we didn't have the internet for great forums like this one to gain knowledge and benefit from other's experiences and knowledge. I am still learning from articles, books and posts from others on this forum. I rarely lose fish now except to old age. We were all a "newbie" at the beginning, and each experience along the way adds to one's knowledge and the hobby becomes even more fun and very rewarding.

You want to ensure you don't overload the system. Twenty tetras (2 inch max size when fully grown adults) in a 20 gallon is fine, if it's planted, gently filtered (water circulating) and weekly partial water changes of 30-40%. Twenty angelfish in the same tank would be asking for trouble and certainly not advisable. In the April 2008 issue of Aquarium Fish International, there is an article on setting up a biotope of the Orinoco River in South America using a tank 30x15x18 inches, which if memory serves me is about 40 gallons. The author, Oliver Lucanus, suggests 118 fish in this setup. In his description of a suitable biotope aquarium for neons or cardinals, Heiko Bleher suggests stocking a 40g aquarium with approximately the same number of fish. In my own experience, I had more than 130 fish in my 90g for several years, and I intend to raise the existing 70 fish to this number if I can ever find the fish I want. In all these examples, we are talking small adult fish being maintained by relatively experienced aquarists. MBilyeu is absolutely correct that clown loaches should be in a group. But, clown loaches can grow to 12 inches, and a group of several of those as adults in a 85g tank (with or without the other fish) would in my view be pushing the extreme too far. However, they are not a problem as long as they are 2-3 inches, but before going down this road you must recognize where it will lead and be prepared.

Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
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post #6 of 7 Old 04-02-2009, 11:03 AM
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I thought it wasnt one fish per gallon, but essentially one INCH of fish per gallon, so for a 12inch fish, about 12 gallons of water. Byrons answer though of course was more complete and helpful!
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post #7 of 7 Old 04-02-2009, 11:34 AM
JohnnyD44's Avatar
one inch of fish would mean you could put a foot long pleco in a 12 gallon wouldn't work......

nice post byron!!!
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