Randall’s Assessor Basslet

Randall’s Assessor Basslet (Assessor randalli) is a small, hardy, and vibrant marine fish reaching a maximum size of 2 to 3 inches. They feature a striking blue to dusky purple coloration with red or orange accents on their fins, which can shift in intensity based on their mood, lighting, and viewing angle. A fascinating trait of this species is their unique upside-down swimming behavior, often cruising under rock ledges and caves inverted. They are generally peaceful but can become territorial toward their own kind.

Tank Requirements
To keep a Randall’s Assessor thriving, your aquarium should meet the following specifications:
• Minimum Tank Size: 30 gallons for a single fish, or 50+ gallons if attempting to keep a group.
• Aquascaping: Provide ample live rock with caves, cracks, and overhangs. They are cryptic and shy initially, requiring plenty of shaded resting areas to feel secure.
• Lighting & Flow: Subdued to moderate lighting and moderate water flow to replicate their natural deep-reef environments.
• Maintaining stable marine environment standards is key to their longevity:
• Temperature: 72°F to 78°F (some sources note up to 82°F)
• Specific Gravity (Salinity): 1.020 to 1.025
• pH: 8.1 to 8.4
• Alkalinity: 8 to 12 dKH

Care & Diet
• Diet: They are strict carnivores. Feed them a variety of finely chopped fresh or frozen meaty marine foods—such as mysis shrimp, brine shrimp, and squid—at least twice daily.
• Reef Compatibility: They are 100% reef-safe and will not harm corals or sessile invertebrates.
• Tankmates: House them with peaceful community tankmates. Avoid large, aggressive predatory fish that may intimidate them or view them as food. If keeping multiple assessors, ensure you only have one male per tank to prevent aggressive territorial disputes.