Very Unpopulated Tank, Visiting LFS Soon

[caligulasAquarium]

Kay, I got a 55 gallon, with two ginormous plecos xD, 3 guppies, and a ghost knife. Yea, I need to get to the LFS, I haven't been able to clean the tank for a while and my gravel vac broke. Ran out of filter cartridges too. So I'm picking up a ton of supplies, as well as some food and some fish.
Plecos measure at a outstanding 15" and 13" (I am trying to give them away or sell them, but have had no luck, none of the LFS can take them in)
BGK measures at 4-6"
Each guppy measure at an inch each, all male
I was thinking of getting a few Dojo Loaches and replacing my four Otos that died earlier in the year, they died within a week, but I was too weary to go back to that store and replace them. Would the BGK eat a loach or Oto? I'm also thinking of getting a few more plants and decor, because the tank is like, half alive and looks ugly. *I've had it for nearly a year now, and gradually getting it to look pretty.* I need to know kinda fast, cause I'm leaving in about 10 minutes.
Thanks!

 

[FeldmansFish]

Depends on the size because if the guppies are alive and they're an inch, you should be fine but not with the otos when the bgk gets bigger

 

[Tippytrampoline]

I wouldn't get any more fish until you're able to rehome the plecostomus. Keeping them in that small of a tank together will create a HUGE bioload, and adding more fish could cause problems. I would suggest replacing your gravel filter and doing regular water changes, and once you've rehomed the plecostomus then start adding new fish. As much as I loved my pleco, the amount of waste it produced was difficult to keep up with and cause lots of problems down the line for the rest of the community. Good luck!!!