55g is enough for one for life. Bigger if u want to keep more than one. Not picky with food but greedy. Solo fish or can be kept in groups(other gulpers) of similar size. Will eat tankmates small as it and even twice its size. Water changes 50% 1-2 times per week should be enough for maintenance depending on feedings and water quality.
Two big problems are eating tankmates (but not other gulpers) 2x-3x longer than themselves and they can be sensitive to water quality and chemical composition.
In nature they live in soft, acidic water and it would look like their adaptability to harder waters is smaller than average.