Best fish for a 55 gallon tank (and how many)

Best fish for a 55 gallon tank

In order of how well they suit a 55 gallon tank. "Up to" is the most of that one species the tank holds on its own; mixing species splits it.

1. 1.Boeseman's rainbowfish Melanotaenia boesemani

   4.3" adult · groups of 6+ · 81–86 °F · pH 7–8 · up to 9 in a 55 gallon

   Keep a shoal of 6–8 or more in hard, alkaline water; Seriously Fish's minimum is 120 × 30 cm. Shop juveniles are drab and can take over a year to colour up.^[1]

2. 2.Swordtail Xiphophorus hellerii

   5.5" adult · groups of 3+ · 61–82 °F · pH 7–8 · up to 7 in a 55 gallon

   Seriously Fish's smallest footprint is 120 × 30 cm. In cramped tanks groups of males form pecking orders.^[2]

3. 3.Rosy barb Pethia conchonius

   3.9" adult · groups of 8+ · 61–75 °F · pH 6–8 · up to 10 in a 55 gallon

   A hardy barb for cooler water (16–24 °C per Seriously Fish) in a group of 8–10, on a 100 × 30 cm base.^[4]

4. 4.Rummynose tetra Petitella rhodostoma (most sold are P. bleheri)

   2" adult · groups of 10+ · 75–81 °F · pH 5.5–7 · up to 31 in a 55 gallon

   Seriously Fish says keep 10 or more in a tank at least 90 cm long.^[5]

5. 5.Pearl gourami Trichopodus leerii

   5" adult · one is fine · 75–86 °F · pH 5.5–8 · up to 8 in a 55 gallon

   One of the most peaceful gouramis; keep one male.^[6]

6. 6.Firemouth cichlid Thorichthys meeki

   6" adult · one is fine · 68–90 °F · pH 6.5–8.5 · up to 4 in a 55 gallon

   One pair fits: Seriously Fish's base for a single pair is 120 × 30 cm. The pair turns territorial when spawning.^[7]

7. 7.Black skirt tetra Gymnocorymbus ternetzi

   2.5" adult · groups of 12+ · 70–78 °F · pH 6–7.5 · up to 17 in a 55 gallon

   A group of 12, the shoal Seriously Fish says usually stops fin-nipping, fits a 55 easily.^[8]

8. 8.Molly Poecilia sphenops

   4" adult · groups of 3+ · 70–82 °F · pH 7–8.5 · up to 10 in a 55 gallon

   Needs hard, mineral-rich water; Seriously Fish's base is 90 × 30 cm.^[9]

9. 9.Corydoras Corydoras spp.

   3" adult · groups of 6+ · 72–78 °F · pH 6.5–7.5 · up to 14 in a 55 gallon

   A group of six or more bronze or peppered corys over sand.^[10]

10. 10.Kuhli loach Pangio semicincta (sold as P. kuhlii)

    4" adult · groups of 6+ · 72–79 °F · pH 5.5–7 · up to 15 in a 55 gallon

    Keep a group of 5–6 or more; the trade 'kuhli' is usually Pangio semicincta.^[11]

11. 11.Bristlenose pleco Ancistrus cf. cirrhosus

    5" adult · one is fine · 70–79 °F · pH 5.5–7.5 · up to 5 in a 55 gallon

    Stays small, unlike the common pleco; Seriously Fish's 60 × 30 cm base suits one fish or a pair.^[12]

Shrimp and snails for a 55 gallon tank

Listed separately: the fish bio-load budget below doesn't describe invertebrates, so they aren't counted in it.

• Amano shrimp Caridina multidentata

  Strong algae eaters that don't need a group; keep a tight lid.^[13]

• Nerite snail Neritidae (e.g. Vittina natalensis)

  Grazes algae off glass and decor.^[14]

• Mystery snail Pomacea diffusa

  Needs hard water, with a pH of at least 7.2 per Aquarium Co-Op.^[15]

How many of each fish fit in a 55 gallon tank

A 55 gallon (48 × 13 × 21 in) holds about 51 gallons of water once you take off the glass. Our stocking calculator budgets that water by adult size and body shape: about 0.8 gallons per inch of slim fish (tetras, rasboras), 1.2 for medium-bodied fish (guppies, corys) and 2 for heavy, messy fish (goldfish, plecos). That works out to roughly 63 inches of small, slim adult fish in total. It is an upper limit, not a target: filtration, plants, territory and how often you change water all move it.

Stocking ideas for a 55 gallon tank

Stocking plans that fit the tank's bio-load budget, with a temperature and pH range that suits everything in them.

Fish to avoid in a 55 gallon tank

• Angelfish · needs 75+ gallons, 40 in long, 16 in front to back

  Seriously Fish's smallest tank is 100 × 40 × 50 cm; a 55 is only about 33 cm (13 in) front to back.^[3]

• Giant danio · needs 60+ gallons, 48 in long, 18 in front to back

  Seriously Fish's minimum base is 120 × 45 cm, deeper than a 55.^[18]

• Discus · needs 75+ gallons, 48 in long, 18 in front to back

  Seriously Fish's base is 120 × 45 cm, and discus need warm, very soft water.^[19]

• Silver dollar · needs 125+ gallons, 71 in long, 15 in front to back

  A group of adults needs at least 180 × 38 cm, a 6-foot tank.^[20]

• Clown loach · needs 180+ gallons, 71 in long, 24 in front to back

  Seriously Fish calls 180 × 60 cm the absolute minimum for a group.^[21]

• Common pleco · needs 125+ gallons, 72 in long

  Reaches about 20 inches and needs a 6-foot tank.^[22]

55 gallon tank FAQ

How many fish can you put in a 55 gallon tank?

Roughly 64 inches of small, slim adult fish by our bio-load method: for example 12 rummy-nose tetras, 6 corydoras and a pearl gourami, or 6 Boeseman's rainbowfish with a pair of pearl gouramis.^{[5, 10, 6, 1]}

Can angelfish live in a 55 gallon tank?

Seriously Fish's smallest recommended tank is 100 × 40 × 50 cm, and a standard 55 is only about 33 cm (13 in) front to back. The smallest standard tank that meets it is a 75; a 60 gallon breeder has the footprint but is only 16 inches tall.^[3]

How many neon tetras can you put in a 55 gallon tank?

Up to about 42 on their own by bio-load, and at least 8–10 so they school.^[23]

Is a 55 gallon good for cichlids?

For one pair of a medium Central American cichlid such as the firemouth, whose Seriously Fish base is 120 × 30 cm, yes. Its narrow depth rules out fish that need front-to-back room, such as the Bolivian ram (90 × 45 cm base).^{[7, 24]}

Can clown loaches live in a 55 gallon tank?

Not long term: Seriously Fish calls 180 × 60 cm the absolute minimum for a group and says they can live more than 20 years.^[21]