Spot Tail Algae Eater (Crossocheilus reticulatus)

Common Name

Spot Tail Algae Eater, Reticulated Algae Eater. You may also see this fish sold as the Silver Flying Fox in some shops, so checking the scientific name is the safest way to be sure you are getting the real thing.

Origin and Habitat

Crossocheilus reticulatus is native to mainland Southeast Asia, with records centered in the Mekong and Chao Phraya river basins. In the wild it is usually found in clear, relatively fast moving water over gravel, rock, and boulder, and it also moves out onto floodplains during high water when food is abundant.

That seasonal floodplain lifestyle matters in the aquarium. Give it oxygen rich water, open swimming space, and plenty of hard surfaces to graze, and it behaves like the confident, constantly busy river fish it is.

Biotope

Here is a documented, same region snapshot for building a realistic Southeast Asian river and floodplain inspired tank. The Mekong system includes habitats that range from flowing channels to seasonally flooded margins, and you can see that reflected in the mix of river fish and floodplain species recorded from Tonle Sap, Cambodia, which is connected to the Mekong during the wet season.

Biotope snapshot, Tonle Sap and connected Mekong floodplain habitats, Cambodia

Fish recorded from the same region, common and often seen in the trade

• Rasbora aurotaenia
• Rasbora caudimaculata
• Rasbora daniconius
• Gyrinocheilus aymonieri
• Trichopodus trichopterus
• Trichopodus pectoralis
• Trichopodus microlepis
• Macrognathus siamensis
• Mastacembelus armatus
• Chitala ornata

Fish recorded from the same region, rarer, larger, or mostly seen outside the hobby

• Datnioides microlepis
• Mastacembelus erythrotaenia
• Notopterus notopterus
• Trichopsis schalleri
• Pangasianodon hypophthalmus
• Pangasianodon gigas

Aquatic plants recorded from the Lower Mekong region, common and aquarium friendly options

• Ceratophyllum demersum, coontail
• Ceratopteris thalictroides, water sprite
• Hydrilla verticillata
• Najas graminea
• Limnophila heterophylla
• Nymphoides indica, watersnowflake
• Lemna species, duckweed
• Azolla pinnata
• Salvinia cucullata
• Pistia stratiotes, water lettuce

Aquatic plants from the same region, interesting, larger, or more specialized

• Nelumbo species, lotus
• Blyxa echinosperma
• Ottelia alismoides
• Utricularia flexuosa, bladderwort
• Eichhornia crassipes, water hyacinth, note that it is invasive in many areas and often illegal to possess

Temperature and Water Conditions

This species comes from tropical waters, with FishBase listing 20 to 24 C, which is 68 to 75 F. In aquariums we like a comfortable mid 70s range with strong oxygenation, steady filtration, and low waste buildup.

Aim for a stable, clean setup rather than chasing a perfect number. Soft to medium hard water is fine, and most keepers have good results in a roughly 6.5 to 7.5 pH range.

Appearance and Size

The name reticulatus is a clue, this fish shows a net like reticulated pattern created by darker scale edges. A bold dark mark at the base of the tail is another useful field mark.

Size matters for tank planning. FishBase lists a maximum of 17 cm standard length, which is about 6.7 inches. Standard length does not include the tail fin, so a full grown adult can look a bit longer overall. In home aquariums, many adults settle into the 5 to 7 inch range depending on diet, space, and current.

Diet in the Wild

In the Mekong system this species feeds heavily on algae and periphyton, and it also takes phytoplankton and small drifting foods when available, especially during flood season.

Feeding in Captivity

This is a true grazer, but it still needs a real diet. Offer high quality algae wafers, spirulina based foods, blanched vegetables like zucchini and spinach, and a rotation of frozen foods such as brine shrimp, daphnia, and bloodworms. If you keep it well fed, it will graze continuously without having to bully tankmates for every bite.

If you are buying this fish for algae control, set it up for success. Bright light, real surfaces, and established biofilm go a long way, and it will happily work both soft film algae and the fuzzier growth that shows up on rock and wood.

Behavior and Tank Setup

Reticulated algae eaters are active, alert, and always on the move. They do best in groups, and a small group spreads out the social energy so one fish is not constantly being pestered.

Tank setup tips

• Prioritize length and swimming space over height, a 36 inch long tank is a great starting point for a group, bigger is better
• Use smooth rock, driftwood, and hardy plants so there are plenty of grazing lanes
• Provide moderate to strong flow and excellent oxygenation, this is a river fish
• Keep the lid snug, quick fish can surprise you
• Choose tankmates that enjoy similar flow and are not easily stressed by active swimmers

Breeding

Breeding this species in the home aquarium is considered rare, and many sources note there is no solid, repeatable evidence of hobby level breeding. In the wild, these fish are thought to follow seasonal patterns, shifting habitat with water level changes.

Some related Crossocheilus species have been induced to spawn in commercial settings using hormone treatments, which is common practice in aquaculture for fish that do not readily spawn in captivity. For most hobbyists, it is more realistic to treat this species as a long term, high value algae eating community fish rather than a breeding project.

Breeder’s Tips

• If you want to try anyway, start with a group of adults and watch for consistent pair bonding and chasing patterns
• Condition heavily with varied foods, including algae based foods and small frozen foods
• Try a seasonal simulation, a cooler dry season period followed by a gradual warm up and heavier feeding, paired with larger water changes
• Use fine leaf plants or spawning mops, and consider a simple egg trap because cyprinids will eat eggs
• If eggs appear, remove adults quickly and keep gentle aeration on the egg area
• For any fry that hatch, start with very small foods, such as infusoria and powdered fry foods, then move to newly hatched brine shrimp as soon as they can take it

Quick Facts

• Scientific name
  Crossocheilus reticulatus
• Common names
  Spot Tail Algae Eater, Reticulated Algae Eater, sometimes sold as Silver Flying Fox
• Adult size
  up to about 6.7 inches by standard length, and often 5 to 7 inches overall in aquariums
• Temperature
  68 to 75 F, 20 to 24 C listed in FishBase, mid 70s commonly used in aquariums with high oxygen
• Diet
  algae, periphyton, and prepared foods, keep a strong plant and algae component in the diet
• Temperament
  active and generally peaceful, best with similarly confident tankmates
• Social
  best in a group of at least 4 to 6
• Tank style
  river or high flow community with open swimming room and grazing surfaces
• IUCN status
  Least Concern

Tropical Fish Co. Notes

This is by far Chris’s favorite algae eater of all time. It is prettier than the standard Siamese algae eater, and in our experience it does a better job at actually eating algae at all stages of life.

We like to keep these in a small group in a mature, well oxygenated tank with real current. Think of them as working fish with personality, they graze all day, they stay sleek when the diet is right, and they make a planted river style setup look alive.

If your goal is an algae focused cleanup crew, pair them with good husbandry. Stable water, reasonable stocking, and consistent maintenance will always beat buying a fish and hoping it fixes everything. These will help, a lot, but they still deserve a setup that fits their natural pace.