Scavengers for a 10 gallon?

Keep in mind that you don't really need scavengers and they'll usually end up making things more messy (remember that they'll produce waste too!). They'll also need to be fed just like your other fish.

That being said, there are a few bottom dwellers that might work. Just the betta and platies will make your tank well-stocked already, though, so watch water quality. 10-gallons aren't too stable and can be tricky to stock if you want a community tank.

The only cory cats that will work are pygmy cory cats. The others are too large and/or active--they'll probably survive in a 10-gallon but won't thrive. Pygmy cories aren't always easy to find and have a tendency to disappear from the pet trade from time to time. You may need to have them ordered for you.

Shrimp are hit or miss with bettas. Some eat them, some leave them alone. If you decide to try shrimp, start with a freshwater ghost shrimp or two. They're very cheap so it won't be as much of a loss if they're eaten. If your betta is good with them, cherry shrimp would be ideal for a 10-gallon. They do best with lots of live plants and hiding spots. They're brightly colored, active, hardy, and breed readily. Amano shrimp are also a possibility. They're larger (perhaps not as likely to get eaten?) but a bit more sensitive than cherry shrimp. No shrimp should be added until you're certain that your tank is stable. I don't think the cherry shrimp would appreciate the salt but the amano shrimp won't mind.

Kuhli loaches are very hardy and a lot of fun. You're right, they don't like salt.

Speaking of salt, there's no reason to be adding it on a regular basis. That defeats the whole purpose. Is there a reason you're using so much? None of the fish you've mentioned need salt in any form. It can be used to combat parasites and bacteria--but that's because the sudden change in salinity harms them. If there's constantly salt in the tank, they'll just get used to it and it'll have no effect. The salt is also hard on your freshwater fish because they'll need to use more energy in osmoregulation (basically, they'll spend a lot of extra energy to flush the salt out).

If you'd prefer an algae-eating fish in the future, check out the bristlenose pleco as opposed to oto cats.

Well, after buying my two platys, my sunset wag started to act stressed out - swimming in place, resting on the gravel, gasping - and so I dissolved a tablespoon of aquarium salt in water before slowly adding it to the tank (directions were a tablespoon for every 5 gallons; I have a 10 gallon). I also raised the temp a smidge - today he's breathing at a slower rate and exploring the plants right along with my other platy. The tank the sunset originally came from had aquarium salt in it as well. I've also read that it stimulates the production of slime coat, and does quite a good job at inhibiting parasites and disease - and I couldn't exactly rule these out since the platy had just been purchased. I've decided that the loaches, and perhaps even the corys, wouldn't be the best of choices with this aquarium. I think I will go with a couple of ghost shrimp, and see what happens when I add my betta in there.

On a side note, I never intended to get "scavengers" (maybe I used the wrong term? xD) with the idea in mind that they would take care of all the clean up and never get fed properly, although having the occasional missed flake eaten up would be wonderful. I by no means intend to use them to make maintenance easier for me, though I'm glad you asked to make sure.

Sounds like the platy was just acclimated too fast. Or ammonia/nitrite poisoning but you probably tested for that so I'm thinking acclimation.

Like I said, the salt works on parasites because they can't handle the change. If salt is always present, it won't be as likely to work. I don't recommend adding salt at all...this way you have a weapon against Ich and other parasites. The idea of adding salt as a "preventative" is outdated information IMO. Most aquarists no longer do so but you'll still find the info out there.

It is true that salt may cause excessive slime coat production. That's not a good thing IMO, it means the fish is irritated (and stressed out). I think that products like "Stress Coat" have lead to people thinking that it's a good thing. Your fish can produce slime coats on their own, no need to stress them out to get them to produce extra "slime" . And if a fish couldn't produce because it's sick, stressing the fish further seems counter-productive.

P.S. I know how difficult it is with so much conflicting information out there. There was a time that I regularly added aquarium salt to my betta tanks. At some point I stopped to think about it...what was I doing it for? Once I realized what the salt was actually doing, I stopped. Now I use it for treating sick fish...and it actually works much better .

Good luck with the shrimp! Don't be disheartened if you lose any of the "tester" ghost shrimp. They're often sold as feeders so it can be tricky to get healthy ones. Whenever I buy a group, I usually lose a few within the first month or two.