Most gobies are from brackish or sea water and need salt and minerals in the water.
Most plecos (including dwarf ones) come from soft water with little to no minerals and no salt.
Plecos and gobies should not be kept together.
Bumblebee gobies and most other gobies do best in a single species tank where you can provide them with the correct water chemistry and offer them frozen (but defrosted) or live foods. Most gobies won't take dry food so you need frozen and live foods for them.
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All fish need water that is free of chlorine or chloramine. These two chemicals burn the fish's gills and can wipe out the beneficial filter bacteria.
If you use tap water and it has chlorine or chloramine in, you need to neutralise the chlorine/ chloramine before adding that water to an aquarium containing livestock (fish, shrimp, snails, etc).