You're just getting 2 fish, correct the EBJD and the BGJD? Then I think you should be ok, I keep pairs of dempseys in a 55 gallon long and 40 gallon breeders and don't usually have any issues. One thing, people don't usually keep an EBJD and BGJD unless they plan to breed them, so just be prepared that the bn pleco may eat the eggs sometimes. The parents usually do a good job at protecting the eggs but the pleco may get to them every so often.