I decided to try again, using what I had learned from my first try. This time, I bought the much cheaper tilapia (and it seemed quite fresh). I cut it large, but I used an equal mixture of lemon and lime juices. The bitterness was gone. I also salted it much more. Half an onion and the other half of the jalapeño, though this time I didn't completely de-seed it.
Also, I didn't have any cilantro as what was left over smelled, strangely enough, fishy. I threw it out.
I mixed it up and let it sit for only about twenty minutes this time before starting to eat. I ate it while I drank an all right Czech beer and watched a Fire game. Here's what I noticed:
The fish started out stringy, but after it had been sitting in the acid for the better part of a half, it was perfectly tender. Definitely, letting the fish steep for maybe an hour would make the ceviche just about perfect (as would letting it sit overnight).
It's very rich. I ate nearly a pound of ceviche and felt rather ill afterwards. I'm sure it was the large amount of acid I consumed (that's citrate, not LSD). It really does need to be drained.
It needed chips or tortillas or tostadas or something.
Cilantro, though a very nice flavor, is not necessary and, at $0.99 a bunch, maybe a luxury I can't afford right now (of course, I paid something like $5.50 for the fish).
The Fire are good, but not great, and they seem to lake the cut-throat mentality of the perennial powers of Houston and DC.
Czech lager is still not as good as English ale, but it does go better with ceviche than the former.