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Freshwater Aquarium/Fish Compatibility with Praecox Rainbows


Hi Richard,
I have a somewhat strange question. I have a 15 gallon tank. I currently have four praecox rainbow fish. I have had my tank for about five years, and I have had these same four fish for about two years, so I would say that my tank is pretty established and my praecox rainbows seem to be doing well. My question is, can I bring in one new fish that will get along with the praecox rainbows? I usually don't bring in one fish at a time. I usually will bring in a few of the same species at a time, but is there a single fish that I could introduce to the tank? A fish that would not usually cause the praecox rainbows to mess with him and he wouldn't mess with the praecox rainbows? I get nervous about fish bullying. Also, I would like this fish to have a similar diet so I wouldn't have to deal with different foods or anything like that. Hope my question is clear. Please let me know if you need additional information.

Thanks so much in advance!!

Hi Eli

There are many peaceful community fish that will work with your Praecox Rainbows. Since there are too many for me to name here, I've provided a couple of links to fish that will work, which include pictures. With 4 Praecox Rainbows in a 15 gallon, you are almost at capacity. I would consider at least one bottom feeder, such as a Cory Cat, and possibly one other fish that is not a schooler, like a German Blue Ram. From the links below, the only recommendation I would make is to stay away from Gouramis, Guppies and Mollies, as they can be a little aggressive in my experience. A single Dwarf Gourami would be fine.

Here are the links

Hope this helps, good luck!


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Richard Hight


I own and maintain several freshwater aquariums from 2 to 180 gallon. I can answer most questions about freshwater aquariums, including setup, cycling, maintenance, compatible tank mates, feeding. Moving? I've moved fish both across town and across the country and can help you get your little aquatic friends to their new home safely. I know and have experience with most freshwater community fish, South American Cichlids and African Cichlids. I don't answer questions about Goldfish or keeping Goldfish with Tropical Fish. I also don't answer questions about keeping crustaceans (shrimp, snails, crabs etc) with Tropical Fish, nor questions about saltwater fish or aquariums. I'm not available to answer questions on weekends, this is when I do maintenance on my own tanks.


Many years of personal experience with community tank fish, semi-aggressive fish (Barbs, Tetras, etc), Angels, South American Cichlids and African Cichlids.

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