I apologize if I have offended you. It can often happen when we have nothing but written text to deal with and no vocal inflections that the writer is being hyper- critical, and I want to assure you that wasn't my intent. Again, sorry.
And I'm glad you have the species that stays manageable in size. Not everyone is so lucky. What I meant by "it's all the same" unless you know the species was not that you aren't knowledgeable, but that not every fish dealer is ethical. You buy fish, as I did several years ago, expecting one thing and then realizing after the fish are grown that they weren't want you had signed up for. (In my case, I bought what were supposed to be Placidochromis Phenochilus and Otopharynx Lithobates juveniles from a local breeder; the fish matured into attractive but clearly cross-bred fish. In this case, even knowing the species, visiting the breeder, and seeing the parents of these fish didn't save me from a huge waste of time).
And I'm glad your eel is an extrovert, because it would be a bummer to have a great fish like that and have it hide all the time.
I think a school of silver dollars would be spectacular in your 125. For what it's worth, I didn't say that I believed a 125 to be inadequate, I simply related the opinion of an accomplished aquarist whom I respect. His mission is rescuing fish that other people give up on: pangasius cats, true giant gouramis, you get the picture. He has a garage full of resealed 125s, tubs, pools, and plywood builds to house the cast-off giants people abandon. Among his many orphans are quite a few silver dollars. . . so that's where that opinion is coming from.
As far as the space issue goes, I don't think we should be defensive about what we have so much as try to do our best. The best I can do today usually can be bettered in the future. The more I look at my own fish, the more scrupulous I have become about evaluating how they use the space I have given them, and the more I question whether they have enough.
I think it's okay to keep fish in "the minimum acceptable tank" as long as you keep in mind that there is also an "ideal sized tank" for that species as well. And, seriously, why would I judge you? I openly admit that I currently have a tank whose residents need more space. It would be hypocritical of me to accuse you of falling short in an area where I am falling short!
Sincerely,
Randy