55G is about 200L or so. i have a tank like that in my house, it's my smallest tank
dimensions are 1.3m x 40 cm x 40 cm.
or in non metrics: 4' 4" length x 16" width x 16" heighth.
Unfortunately a standard US 55 (the most common mid-size tank in the States) is 48" X 12.5" X 20.5" so it is worse than what Sid thought (i.e. narrower and taller, which does not help the fish in question). The next size down is a US 45, which is 48" X 12.5" X 17".
A US 55 actually holds 53.24 gallons (201.53 liters) before filtration, gravel, rocks, driftwood, etc, although the above tank looks quite bare.
24" of doradid and 12" of plecos, still way under the 1" of fish per gallon rule
In all seriousness Skwerally, you are looking at needing a much, much larger tank (better yet a heated indoor pond) for your animals.
-Shane
"My journey is at an end and the tale is told. The reader who has followed so faithfully and so far, they have the right to ask, what do I bring back? It can be summed up in three words. Concentrate upon Uganda."
Winston Churchill, My African Journey