IDK what a jaguar dolphin catfish is. Is it a species from the Ageneiosus genus
https://www.planetcatfish.com/common/genus.php?genus_id=105 ? Fish from this genus appear to be an exception in the family in that they don't hide but swim constantly.
In general, the rule of thumb is that the minimum tank footprint size is 4L x 2L where L is the total length of fish. For an active swimmer, it is larger, like 6L x 3L. So for one-foot fish, the minimum tank length and width are 4'x2' and 6'x3'. You can run down the list of your candidates by their max size and see which ones fit this requirement... if your plan is to keep them in that 75 gal until they reach their max size.