My 29 gallon has 1 blue gourami, six harlequin rasboras, and six peppered cories. Can I add some fancy guppies (keep in mind I know that I am stocked when the current inhabitants are full grown but in a year or so I'm moving the gourami). Basically, will the rasboras or gourami attack them? Thanks.
I really only have one comment and it is not an answer to your question, I am sorry to say. I do hope that you are not planning to put the gourami in with Satin. They are related and the effect would be the same as putting two male Bettas in together. I hope this does not upset your plans too much but I thought you should be told now than down the line when it might cause a real problem.
As long as you are not planning on moving your Betta back to the 29 gallon I don't see why not. But I would wait until you have moved the Gourami. You don't want something to come up that prevents you from moving the Gourami and end up with an overstocked tank. As far as I know Harlequins are very peaceful. I'm not sure about the Gourami.
Gouramis as a group are rated as "Semi-Aggressive", the same as the Betta. (Surprise, the Betta is a member of the Gourami family!) The behavior is essentially supposed to be the same, territorial and can be belligerant to others in the same family. I wouldn't want to put them in with anything you wouldn't put in with a Betta, they are after all related.
OK thanks for the advice... yeah i wasnt planning on putting satin back in the 29. I think the ten is his new home... he seems happy and once his plants come I think he will forgive me. I dont think I'll have a problem moving the gourami later though so I might just go ahead and get the guppies now.