Mexican Tetra (Astyanax mexicanus) is a beginner-level freshwater fish that needs at least 30 gallons and 68-77°F. A hardy, silvery tetra that tolerates cooler temperatures than most tropical tetras. The sighted form and the pale, eyeless blind cave form are the same species. Blind fish do well with calm tankmates and an unchanged tank layout.
Care facts at a glance
| Scientific name | Astyanax mexicanus |
|---|---|
| Family | Characidae |
| Origin | Texas, New Mexico and Mexico (surface form); caves in Mexico (blind form) |
| Adult size | 3-4 in |
| Minimum tank | 30 gallons |
| Temperature | 68-77°F |
| pH | 6.5-8.0 |
| Temperament | Active, may nip slow or long-finned fish |
| Social behavior | Schooling, keep 6+ |
| Swim level | Mid |
| Difficulty | Beginner |
| Diet | Omnivore: flakes, small pellets, frozen foods |
| Typical lifespan | 5-8 years |
Quick tips
- Keep a group of six or more.
- Avoid long-finned or slow tankmates; they may be nipped.
- Blind fish find food by smell and touch; do not rearrange the tank often.
San Diego water
Tolerates San Diego's hard, alkaline tap water (pH roughly 7.6-8.6) with slow acclimation and a conditioner that handles chloramine. Learn the numbers in our San Diego tap water guide.
Before you buy
Make sure your tank is cycled (how to cycle a tank), check your numbers with the water testing guide, and use the compatibility guide to check tankmates. These are general ranges; individual fish and local water vary.
Find it at Pet Zone
Pet Zone Tropical Fish is a San Diego aquarium store with two locations. Stock changes daily, so call ahead if you are after a specific species or plant. Shop online at petzonesd.com.
4160 Convoy St, San Diego, CA 92111
(858) 987-0309
Open daily, 10am-6pm
Aquascaping, planted tanks
4266 University Ave, San Diego, CA 92105
(619) 283-1812
Closed Monday; Tue-Fri 10:30am-6pm, Sat 11am-6pm, Sun 11am-4pm
Monster fish, koi