Personally, I have never had more than one AST, but I used to keep my Florida snapper with my AST, and I was forced to separate them when the the FL got to be around 6 inches. It was bullying the AST around the tank, but I never witnessed either biting the other.
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Bill
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1.0 Banded Cal King
0.1 Striped Cal King
0.1 Aberrant Cal King
0.1 Chihuahua Mountain King
1.0 Arizona Mountain King
1.0 Anery Jurassic Milk
1.0 Nelson's/Corn snake hybrid
0.0.2 Viper Boa
1.0 Blue Tongue Skink
2.3 African Dwarf Frogs
0.0.1 Alligator Snapping Turtle
0.0.1 Florida Snapping Turtle
0.0.1 Loggerhead Musk Turtle
0.0.1 Common Musk Turtle