you can't keep a softshell in a rio 125 unless its a hatchling a male gets to around 1ft and a female gets around 2ft so you will need a 5ft x 3 x 2 minimum if you end up with a female. Recommended size for a single adult Apalone ferox would be a 75 gallon aquarium as a minimum (90 or larger preferred) for a male. It is not recommended that female Apalone ferox be maintained in conventional aquariums. They are too large as adults and require an extreme amount of space. Stock tanks would be the ideal choice, with a minimum requirement of 400 gallons (600 gallon or larger preferred). This will provide adequate swimming area, as well as assisting the filtration in maintaining good water quality. For additional male Apalone ferox, I would recommend adding 75 gallons of tank space per additional turtle at a minimum. For a female, add no less than 100 gallons of space, per turtle.
This turtle does bask, so a basking spot will need to be provided. They prefer deep, soft-bottomed habitats, with a lot of vegetation. A shelf that is submerged just below the surface of the water that allows them to rest underwater yet reach their neck up and breath is also recommended. Either artificial plants or aquatic plants are suggested, although both types my be dislodged by the softshell when it buries in the substrate. The substrate, if used, should be sand. UVB 10.0 lighting is required, as well as a heat lamp over the basking area. A submersible heater is also recommended. Sharp decorations and rough terrain features should be avoided, as they can often bring injury to softshelled turtles. Water depth should be as deep as possible.
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