Ah, that makes sense, but if you don't get lucky with getting two of the #1 Magic Fish, then all it'll take is to buy another set of common eggs. (So far all the sets I've bought contained at least one of those...)

I was breeding golden goldbulbs like mad, but not using the growth hormone and waiting to buy that second tank until after I bought the envirnoment research, so it took longer, but effective.