Well, as you can see from my sig, I'm into aquariums. I also love snakes, although I've found they get boring pretty fast. I guess I like the interaction.
Anyway. Maybe what you've been doing in your 55, fish wise, needs a change. There's an endless variety of options out there. If changing filters and cleaning gravel turn you off, do a planted tank. You don't need filters with a planted tank because the plants use those nutrients. Same with the stuff on the substrate. Let the plants have it. As far as algae and plecos go, not all species of plecos eat all types of algae, no matter how hungry they get. With careful species selection and stocking levels you can even reduce the partial water changes, too. Too many people make fish keeping harder than it has to be. I have many aquariums and most don't have filters and I rarely need to siphon more than just across the top of the gravel in the very front of the tank (for visual appeal).
Just another option.
About selling your fish. You could give them away on Craigslist or FreeCycle or sell them on
eBay. What ever you choose to do you should state that all transactions are final. As I'm sure you know, there's a lot of people out there that don't understand how to acclimate fish, and probably more that don't understand how the nitrogen cycle works and what they would have to do in order to get the fish through their tank's cycling. You could offer your knowledge. One place that's likely to have more fish experienced people that would buy them is Aquabid. Because you're not a breeder you likely wouldn't get a huge amount for them. No matter where you sell them, you're likely not going to get even 1/2 of what you paid for them. That's because the fish aren't young anymore and there's more of a risk of spreading disease when the fish are coming from someone who's not a breeder. The fact that they originated from
Walmart, or any fish store that has fish coming in from various places that can't quarantine them is risky.
If you need advise on shipping fish, drop me a PM and I'll walk you through it.
Good luck with whatever you decide to do.