Actually, (though I don't have direct experience with this) it says on Doug Dix's site:
"Uros are by nature territorial, and even calm animals tend to attack new individuals placed in their cage. A notable exception occurs between individuals of vastly differing size. In particular, large adults are very tolerant of sharing their cage with small juveniles, the bigger the size difference, the better."
My experience was with two Saharans (who are supposed to be more roommate-friendly than Malis) - a male and a female, both wild caught young adults. The male was only about 50g heavier than the female.
What Doug Dix told me to do when I bought Joe was to soak them both at the same time, completely rearrange the cage furniture, then introduce them to the cage at the same time. It's best to move the male into the female's cage. Then I had to sit and watch them for several hours to be sure no fighting occurred, and be aware for several months to check for fighting marks. They treat each other like furniture, so it was no problem for me.
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Torey
Eugene, Oregon, USA
1.1 Uromastyx Geyri (Joe and Arthur)
2.0.1 Uromastyx Dispar Maliensis (Tank, Turtle, and new neighbor Spike)
1.2 Anolis Carolinensis (Bowser, Leeloo, and Sprocket)
1.1 African Dwarf Frogs (Bruce and Sheila)
1.0 Betta Splendens (Mr. Miagi)
1.1 Felis Domesticus (Roscolux and Jenny)
And several miscellaneous community fish
