First off stay away from FH, and oscars.
Grammodes are great and I have one. They are not for every fish keeper as u need great patience to own these guys. My female didn't come out of her shell until a few months ago and I've had her almost 2 years. Males get much bigger and make better glassbangers then females but again they grow slow and u have to wait for them to trust you and that can take a while.
As far as parachromis species, the loiselli isn't a great glassbanger. U have a jag so why go that route unless you go with a dovii and you could easly get 2+ years in a 75 with a dovii.
Veja are very good solo fish but I've never really seen glassbanging veja. Blackbelts are a great choice tho.
Any type of midas or devil will be glassbangers atleast u hope. My 2 red isletas are far from glassbangers which really angers me but whatever...
Umbee is another choice and u could get a 2 years outta them in a 75.
Now the one I would really suggest would be a Amphilophus hogaboomorum. That's a lifer for ur 75. My second choice would be dovii as long as you can house it as it grows. Third choice grammodes male
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