The term “waterdog” refers to the aquatic larval stage of certain salamanders, which are strictly carnivorous. Their diet must be high in protein and closely mimic the diverse invertebrate prey found in their natural aquatic habitats. Understanding the specific species commonly given this name is the first step toward providing proper nutrition and preventing deficiencies in captivity.
Identifying the “Waterdog”
The common name “waterdog” is broadly applied to two distinct groups of gilled, aquatic salamanders, which can cause confusion regarding their care. The first group is the Mudpuppy (Necturus maculosus), a species that remains aquatic throughout its entire life, a process known as neoteny. Mudpuppies are characterized by their bushy, red external gills and four toes on each foot.
The second group includes the large, gilled larvae of the Mole Salamander family, specifically species like the Tiger Salamander (Ambystoma spp.). These larvae are frequently sold as “waterdogs” but are expected to eventually undergo metamorphosis, lose their gills, and become terrestrial. Although their final life stages differ, the immediate nutritional requirements of both the Mudpuppy and Ambystoma larvae are similar as aquatic, gilled carnivores.
Wild Diet and Foraging Habits
In their native environments, waterdogs are opportunistic, ambush predators that spend most of their time foraging on the bottom of lakes and rivers. Their diet is primarily composed of aquatic invertebrates, which provide the high protein and mineral content necessary for development. Larger individuals, such as the Mudpuppy, consume crayfish, alongside insect larvae, mollusks, and aquatic worms.
Smaller larval forms and juveniles focus on smaller prey items, including copepods, cladocerans, and midge larvae. Waterdogs rely on their lateral line organs to detect the vibrations of nearby prey in murky water, often foraging nocturnally. They employ a “suck and gape” method, rapidly opening their mouths to create suction and draw in the prey.
Essential Nutrition for Captive Care
Captive waterdogs require a food regimen rich in protein and low in fat, mimicking their wild diet. The best staple food is the live earthworm, or nightcrawler, which offers a complete source of protein and essential nutrients. These should be cut into pieces appropriate for the salamander’s mouth size to aid consumption.
For variety, high-quality, sinking carnivorous pellets formulated for aquatic amphibians or carnivore fish can be incorporated, but should not form the bulk of the diet. Other acceptable options include frozen and thawed foods such as bloodworms, brine shrimp, and krill. Fatty foods, like goldfish, waxworms, or pinky mice, should be avoided as they can lead to liver damage and other long-term health issues.
Because aquatic salamanders do not receive UV-B light to synthesize Vitamin D3, they require this vitamin and calcium to be supplemented in their food. This is achieved by coating or “dusting” food items with a high-quality calcium powder that contains Vitamin D3. A separate multivitamin powder is often used in rotation to ensure a broad spectrum of nutrient intake. Supplementation prevents Metabolic Bone Disease (MBD), which is caused by an inadequate calcium-to-phosphorus ratio.
Feeding Schedule and Health Monitoring
The frequency of feeding must be adjusted based on the waterdog’s life stage and size. Fast-growing juveniles and larvae should be fed small meals daily or every other day to support their development. Adult waterdogs, particularly Mudpuppies, have slower metabolisms and require feeding only two to three times per week.
A general rule for portion control is to feed only what the waterdog can consume in a few minutes, ensuring the prey is no larger than the width of the salamander’s head. Uneaten food must be removed promptly, usually within 15 to 30 minutes, to prevent the decay of organic material that fouls the water and introduces harmful bacteria. Target feeding, using tongs to offer food directly, helps monitor consumption and minimizes waste.
Health monitoring involves regularly checking the salamander’s body condition, particularly the thickness of the tail, as thinning indicates inadequate nutrition or energy reserves. A refusal to eat, lethargy, or visible skeletal deformities, such as a curved spine or soft jaw, are signs of potential malnutrition, especially calcium deficiency. Maintaining a precise feeding schedule and strict water quality parameters are integral components of a proper diet plan.