I house one of my pairs together and never had a problem. As stated above, make sure they're similar in size as well as a chance of them accidentally breeding.
I've heard of two males fighting when put in the same enclosure but I've nevet done that so I don't have any personal experience with that.
Other than that, there shouldn't be any issues. At least i never had any. But if you're second guessing it, just get another tub and have them seperately.
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