1' of fish per 1 gal of water. Fact or Fiction

aqua_jerryJuly 27, 2006

I have received feedback on fish that I have not being in suitable quarters. I have read, the rule of thumb, 1" of fish for 1 gal of water, however; it appears there is more to this theory than is published, i.e. I have 2 Angels and a Pleco in a 29g tank. est combined size of these fish at maturity 22". 16g tank, 2 platies, 1 Clown Loach, 1 Rubber lip, est combined size at maturity, 12". While close, and clearly not able to know exactly the size of the fish growth, what additional considerations need to be made when populating a tank?

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Not fact.

Fish are so many different shapes! It's not just length, but width and depth (or roundness?) Angels are totally a different shape from neons, for example. A three inch killie is a different shape from a 3 inch ram or a 3 inch mollie.

IMO, clown loaches love company - and do better with company of their own kind. They're very social schooling fish. My loaches are in a 72 gallon... and they love zipping from end to end, and they like to huddle together when they rest in a hollow resin log that I have in the tank. My largest clown is about 7 inches long and about 2 1/2 inches high. Clown loaches are gorgeous fish and very fun to watch. But I think for smaller tanks, cory cats are equally beautiful and fun to watch. They're smaller and more compact and also love company of their own kind since they also like to school.

If you have a common pleco - a 29 gallon simply is not large enough. No two ways about it. Common plecos get VERY big and produce a lot of waste.

Angels can get as big as 5-6 inches (including fins). I've found that if angels are in too small a tank and they're not a pair, they tend to get aggressive and territorial. Just not enough space to establish territory.

There are lots of fish that I would just love to have in my home! Like Discus! But I don't have room for another tank, and they're the sort of fish that you can't just throw in with other fish.

So I'm happy with my community tank. Lots of action and various types of fish. Maybe they're not flashy and rare, but they're fun to watch.

I have a 12 gallon tank that I keep at my job. Resident are four cory cats, one dwarf gourami and two glass cats.

    Bookmark   July 27, 2006 at 8:08PM
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woeisme(z7b NC)

It is just that "rule of thumb", for platys and similar shaped fish this is accurate. A full grown common Pleco gets 12"+ At 12" even a 15 gallon tank would be too small, However, 20 neons tetras would be fine in a 10 gallon tank. Just use good judgement take into consideration the measurement of the fish, and body shape along with it's needsand habits. Peacock Mbuna Cichlids need alot of swimming space, so even though some may only get 5" as adults, they need lots of swimming room back and forth.

    Bookmark   July 28, 2006 at 7:50AM
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Is it ok to add some small Tetra's or others to my tanks now? I am concerned that my Angels may be agressive towards the smaller fish.

Or, should I move my CL to the 29g, and get him a friend while I ponder the destiny of my Pleco?

Any advice is greatly appreciated.

    Bookmark   July 28, 2006 at 6:13PM
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Please don't do anything new until your tanks are better established.

Don't move the loach yet. Too soon. Clowns sometimes are more fussy about water conditions.

I know the feeling of wanting to do more right away. But definitely take the lessons learned from all of us here and just wait it out a bit longer. Be patient and your fish will appreciate it!

    Bookmark   July 28, 2006 at 8:49PM
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Another thing to consider besides gallonage is the shape of the tank. For instance, angels like a tall tank, and white clouds like a long tank. Also, there's the territory factor. If you have a 50g long tank, you can keep two male bettas, because they'll each establish their territories on opposite sides. But if you had a 50g cube-shaped or tall tank, they'd likely fight. Don't just dismiss the inch rule, though. It's a very good place to start.

    Bookmark   July 29, 2006 at 1:30PM
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i got this from "the aquarium fish handbook" by dick mills and derek Labert:

Tropical Freshwater: 1 in body legth of fish per 12 sq in of water surface

Coldwater Freshwater: 1 in body legth of fish per 30 sq in of water surface

Tropical Marine: 1 in body legth of fish per 48 sq in of water surface

    Bookmark   July 30, 2006 at 1:05AM
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Inches/water surface ratios are to ensure an adequate oxygen level, unless I'm mistaken. Filters and bubblers allow you to get away without paying attention to those, mostly. Rules are really over-simplifying things though. You wouldn't put a 10" goldfish in a 10g tank, nor would you put it in a puddle measuring 300"^2.

The best way to go about it is to read about the particular fish to make sure of the care it requires. I love Google because you can get many opinions from many places, and chances are that when many websites say the same thing, it's true. After all, why would the majority be lying? People make fish websites because they like fish, not because they want your fish to die. That's my reasoning, anyway. Of course, there are the sites that just want you to buy their fish, but that's different.

    Bookmark   July 30, 2006 at 2:05AM
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Aqua Jerry, remember the food chain when thinking of adding fish to your tank. ie: big fish eat small fish. I learned that the hard, tearful way.

    Bookmark   July 31, 2006 at 12:59PM
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The bulk of the fish have a lot to do with it. 10 1" Tetras would most likely be fine in 10 gallons of water but no way could you keep a 10 inch Oscar in 10 gallons.


    Bookmark   August 1, 2006 at 9:52AM
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Hi there!
I am a newer owner of my freshwater tank. Finally, everything was running incredible for the last couple of months and of course it was to good to be true. My moor has an eye that is so big, it's unbeleivable. So I figured pop eye and went to the pet store for treatment. They said it could also be a fluke in his eye. Anyways, I put him in my hospital tank and am using Maracyn-Two and am on the sixth day and no change in his eye. I also tried salt for a couple of days and it did nothing either. The instructions say 1 tablet per 10 gallons daily. Mine is a five gallon so I have been putting half a tablet. Do you think that is a sufficient amount and will anything ever happen. It says to try for five days and then continue for another five if nothing happens. Any advice out there? Anything is greatly appreciated as it is killing me to watch him like this and the thought of losing an eye kills me. Thanks.

    Bookmark   August 9, 2006 at 8:10PM
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jill1979, describe what the eye looks like, do you see anything coming out, an open sore or a worm? with the maryacyn two, i have a 1 gal hospital tank, i am treating one of my goldfish right now aproaching the last few days of tx & what i have done is cut the tablet in ten peices, i am only using 5 peices, as the 1st day you treat you double dose.... so i save the extra for next time......

    Bookmark   August 14, 2006 at 6:24PM
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I agree that the 1" per fish "rule" is overly simplistic, because different fish need different amounts of swimming room, vertical and/or horizontal.

The 1" rule also dates back to pre-power filter days and fails to account for the filtration and water circulation that can be accomplished with the equipment now available.

There is also the difference between fish simply surviving, and fish thriving.

My 2 fat, useless, but tame and charming 12" pet Goldies are currently surviving in a 29, while their 65 is being made ready for different species, and a new 80 is being set up for them.

However, to insure they will continue to survive in their confinement, the 29 is being filtered with an Emperor 400, there is a 12" airstone fed so much pressure one entire side wall is pure, strong bubbles, and they are water changed down to their dorsals weekly.

One might think that 24" of fish would be fine in 29 gallons, but either of them represents the weight and BULK of at least 50 guppies and as Cold Water fish, they need more oxygen than Tropicals.

I believe the key to the OP's question is to know what each species needs, and work from there.

BTW: Just 2 Angels and 1 Pleco should do fine in a 29, but I couldn't keep a Common, as they get too big. A better choice would be one of the smaller species, such as a Bristlenose.

    Bookmark   August 21, 2006 at 11:18AM
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