Hmm. Shrimp are a maybe, as they don't mind gravel, but might get eaten by the ram or sword. Cories can do a better job if the gravel is not too rough though. I use loaches too, but they really do need sand.
of course that's all about bottom feeders. If you are talking abot algae, that another fish entirely. Smal plecos are pretty goood with that group. Rubber nose plecos and pitbull plecs would do a good job. Otos are good at it, if you have softer water. They are more fragile then the others, however.
hope that helps.
Cory cats should be in a group of six if your tank is big enough. A bristle nose plecco stays small, my lemon pleco L144 will top out at 4 inches and my albino BN plecco is also 4 inches. they live in different tanks. IMO a 29 gal tank would be fine for the cories, and a small pleco that won't outgrow your tank, and shrimp have a very small bioload and the ghost shrimp won't reproduce
in fresh water. Alison
I wouldnt get corys, or any loaches with gravel. They dig thru the substrate to eat and the gravel would really wear down their barbels. That can lead to infections, death, or fish that can find their food.
If your talking about algae, a pleco or snail would be okay(small Pleco)
If your talking about uneaten food, I would try to cut down on the amount you feed your fish.
Try to figure out why you have either uneaten food or algae and work on that. Also, any fish that would be considered "clean up crew" really shouldnt survive solely on scraps the other fish have missed. They would all need supplemental feeding. I would look into ghost shrimp, they are cheap and do a good job of cleaning up.
I keep cories and plecos because I like them. you can keep cory cats on smooth gravel just not sharp gravel. Mine get shrimp pellets, alges wafers for the pleco as well as the shrimp pellets, and each plecco gets a chunk of fresh veg every day. Sand is nice but I don't like dealing with it and have always used gravel but that is just my personal preference. the cories do fine on it. Alison
While fish or inverts are a great HELP in cleaning the tank, they are not the main source of cleaning. We have to be the best cleaner of the tank. As others suggested a good gravel vacuum is essential to keeping the tank clean and providing for a good environment. So you can't rely on any "cleanup crew" to do much more then just help a little bit.
With that being said, I would suggest some ghost shrimp (you currently have 2, but 5 more would help a bit), a bristlenose pleco (they stay smaller and are great for certain types of algae), and maybe some snails such as Malaysian Trumpet Snails. The MTS are great for planted tanks, as they dig around in the substrate to help break things down so the plants can use for fertilizer, they also aerate the substrate. They are small and can climb onto almost any surface or décor to help clean things up like algae, detritus, etc.
Remember you don't want to put a ton of fish in, as all animals contribute waste to the environment, so adding more waste to something you are wanting help cleaning is not the solution. The few things I suggested will not add too much waste, while still being helpful to break things down for your filter to process.
Wish you lived near me, you could come over and have a bristle nose, mine are breeding reasonably frequently. There are smaller types. Pitbull plecos are smaller and gentler from what I hear.
MOst peeps feed their plec cucumber, but if you give it a piece of spinach it will love you forever . Mine also eat green peas and occasionally lettuce or corn kernels. Lettuce is their least favorite and corn, justan occasional treat.