With their long, narrow bodies and armored appearance, toothpick fish (Indostomus paradoxus) make stunning additions to any nano tank or planted aquarium. Though they may look tough, toothpick fish are quite congenial.
If you’re thinking about adding these fascinating little fish to your setup, this toothpick fish care guide will help you do it right.
Species Snapshot
· Species Name: Indostomus paradoxus
· Common Names: Toothpick fish, armored stickleback
· Size: 1 inch
· Lifespan: Up to 5 years
· Native Distribution: Myanmar
Relatively new to the aquarium trade, toothpick fish are quickly becoming popular. Their distinctive appearance and docile natures make them a suitable choice for smaller community tanks as well as nano tanks.
Plus, they’re adaptable to both clearwater and blackwater habitats. Because toothpick fish can be sensitive to poor water quality, however, they’re best suited to experienced aquarium hobbyists.
Here's what you need to know about toothpick fish and how to care for them properly.
Anatomy and Appearance
Indostomus paradoxus is one of just three species within the genus Indostomus, the sole genus in the family Indostomidae. In fact, the toothpick fish was thought to be the only species in the genus for 70 years after it was originally described by Prashad and Mukerji in 1929.
However, in 1999, two additional species were described: Indostomus crocodilus and Indostomus spinosus.
Known as both the armored stickleback and the toothpick fish, this species lives up to its names. Indostomus paradoxus grows to a maximum length of just over 1 inch (25-30mm) and exhibits a long, narrow body that tapers toward a small, fan-shaped tail. Their bodies are heavily armored and neutral-colored, which helps them blend into their habitat.
Though toothpick fish are sexually dimorphic, their small size makes it difficult to distinguish anatomical differences. Adult males tend to have broader, more elongated pelvic fins with inward-curving outer rays.
The pelvic fins of female toothpick fish, by contrast, are straight and slender. Females also display a full, rounded abdomen when they are gravid with eggs.
Ideal Aquarium Setup
The toothpick fish is native to Myanmar. Though originally described from the northern region in Lake Indawgyi, it’s also been found in tributaries of the Irrawaddy River and further south in the river’s delta region near Einme. These environments feature slow-moving or standing waters heavy with vegetation and green algae.
While toothpick fish may be adaptable to a variety of planted tank setups, replicating their native environment gives you the best chance for success with this species. Here are our recommendations:
Tank Size
Because they reach a maximum size of around 1 inch, toothpick fish are the perfect nano species. They’re best kept in groups with at least five of their own species in tanks 15 gallons or larger. Larger tanks provide more room for these peaceful fish to explore and can accommodate more vegetation.
Water Parameters
Toothpick fish prefer soft, slightly acidic water with a temperature range of 72-80°F. Their preferred pH range is 6.5-7.5, and water hardness should be kept under 10 dGH.
Captive-bred species may be more adaptable than wild-caught specimens, but consistency is key when it comes to maintaining high water quality and optimal chemistry.
Though toothpick fish prefer slow-moving water, adequate filtration is essential. Sponge filters may be more appropriate than high-flow options like canister filters—they also support healthy biological filtration, which is important. Incorporating live plants into your tank will help with oxygenation and nutrient control, but regular water changes are still recommended.
Tank Décor
The ideal aquarium setup for toothpick fish is a densely planted aquarium with soft substrate and diffuse lighting. Decorate your tank with driftwood roots and branches to create a natural aesthetic. The addition of leaf litter and floating plants will help your toothpick fish feel more at home.
Diet and Feeding
Toothpick fish are micro-predators, so they feed primarily on insect larvae, tiny crustaceans, and zooplankton in their native habitat. In the aquarium environment, these fish are known for being fussy eaters.
They may not accept dried or frozen foods, so be prepared to offer a variety of very small live foods like baby brine shrimp, Daphnia, and micro worms. In mature planted tanks, naturally occurring microfauna will offer some sustenance as well.
Temperament and Tank Mates
The toothpick fish’s personality matches its size, so it’s important to avoid keeping them with any species that are too large or aggressive. Other nano fish make perfect tank mates, especially those with similar dietary requirements.
Toothpick fish are notoriously poor competitors, however, so pay close attention to ensure they’re getting enough to eat.
While toothpick fish aren’t quite on the level of being a shoaling or schooling species, they seem to benefit from living and interacting with others of their own kind. A group size of 4-6 toothpick fish appears to be ideal.
Male toothpick fish may develop territorial tendencies toward other males but rarely cause any significant trouble.
Breeding Toothpick Fish
The successful breeding of toothpick fish has been achieved in captivity, but it requires special circumstances. This species typically spawns in small caves or crevices, with males selecting the spawning site and defending the area around it.
During spawning periods, male toothpick fish grow lighter in color and may take on a reddish hue with a light brown stripe appearing on the dorsal and anal fins. Males court females with displays of erect fins and quivering movements, usually near the entrance to the chosen spawning site.
If breeding is successful, female toothpick fish will deposit the eggs on the roof of the spawning site. Typical clutch size ranges from 5-40 eggs. After depositing the eggs, the female leaves, and the male becomes solely responsible for the eggs until they hatch and the fry become free-swimming.
Raising toothpick fish fry is particularly challenging as they are incredibly small when they hatch. It may be difficult to see them, let alone siphon them out to place in a rearing tank. If you’re successful, you’ll need to offer microscopic foods until the fry are large enough to accept bigger prey.
Conclusion
Toothpick fish bring a unique charm to any nano or planted tank, and with proper care, they can truly thrive. If you're ready to welcome these delicate micro-predators into your aquarium, explore our premium nano fish and live food offerings at Shrimpy Business.
And if you need help fine-tuning your setup, contact us today for expert tips and support.