Coldsprings,
Don't count yourself out on the project yet.
The RES is probably female. If you could post a pic of the vent area a better determination could be made. Were it male, chances are that you would have gotten some milt from your extrusion attempt.
As I understand it, RES girls dress kind of scantily and find themselves in places they should never have been. The chances are that the two will hookup if only they both would be ready when she is. You can get them both in the right state of body and mind with luteinizing hormone so that they mate on your schedule (not theirs). Usually a male is given one dose while the female two where the timing is specified. This can encourage them to mate naturally or allow you to express gametes for an artificial spawn. There are multiple sources online that describe the dosage and methods. I think you could obtain it from a vet that also services agriculture. Fish given the hormone should not be eaten for a minimum of 6 months and the offspring should be unaffected. As with all things of this nature, be careful with syringes and follow best practices for disposal of the waste and or unused medication.
A pond setting with a few pairs would probably also work better than the tanks but since you are using a laboratory setup it might help to use a lab method to control the timing of the mating.
