Skinny Neon tetra+ 2 FAT Neon tetras+ slightly fat Neon tetra. EGGS?

I have a tank of fish and I have got one of those black goldfish with the puffy eyes (Who is nice and when I thought their were eggs before (not any neon tetras yet) and he kept spitting it out), another fish (unknown), 2 zebra fish which are VERY MEAN, and we just got 4 Neon Tetras. One of the neon tetras is normal another is ever so slightly fat. The other 2. blimps FAT fish. Do I have a chance to end up with eggs? If so what do I do?