ORA Yellow Assessor

Quick Stats

• Care Level: Easy
• Diet: Carnivore
• Temperament: Semi-Aggressive
• Reef-Safe: Yes
• Source: Captive Bred
• Approximate Purchase Size: 1.25-1.5"
• Approximate Max Size: 3"
• Recommended Tank Size: 30 Gallons or Larger

Overview

This fish is shipped directly to you with exceptional care and high-grade packaging specifically made for live animals from our partner, ORA. This animal is certified by the Mr. Chili Sustainability Alliance, meaning it is sustainably bred, was raised with exceptional husbandry practices, and 2% of net proceeds will be donated to support Ocean Conservation.

The Yellow Assessor (Assessor flavissimus) is not a member of the Dottyback family, but they are similar to them in many ways. The Yellow Assessor is native to Australia and is a member of the Plesiopidae (Longfins) family that includes the Marine Betta (Comet). They are not nearly as aggressive or territorial as the Dottybacks, and feed on small zooplanktonic crustaceans.

They are fascinating fish that exhibit unusual behavior. In nature, as well as in the reef tank, they can often be found swimming upside down. This is an adaptation used in their habitat where they’re usually found in caves or under ledges. Creating a similar habitat in the aquarium will allow them to exhibit this unique swimming behavior.

The Yellow Assessor will not bother invertebrates in the reef aquarium and will accept most frozen and dry prepared foods.

Note: Image is a representation of what to expect. The fish you receive may vary slightly in appearance.

Aquarium Requirements

Aquarium Size

More space is always beneficial, but a minimum tank size of 30 gallons is recommended for the Yellow Assessor. A larger tank offers more stability in water parameters, which is beneficial for all inhabitants.

Habitat Recommendations

Yellow Assessors are quite adaptable but thrive best in an environment that mimics their natural habitat. Here’s how to set up their ideal home:

• Aquascaping: Yellow Assessors are usually found hanging out in caves or under ledges, often swimming upside-down. Creating similar rock structures in the aquarium will allow you to view this unusual, but fascinating behavior.
• Substrate: This fish has no specific substrate requirements and can be kept in aquariums using sand of various grain sizes, crushed coral, or no substrate at all.

Water Parameters

Maintaining proper water parameters is crucial for the health and well-being of your fish. While Yellow Assessors are considered relatively hardy, providing a stable environment will allow them to thrive and stay healthy.

• Temperature: Keep the water temperature between 75-78°F. Stability is key, so use a reliable heater that can limit any temperature swings to about +/- 1°F or less.
• pH Level: This fish will do well in a wide pH range from about 7.7 to 8.5.
• Salinity: The specific gravity should be between 1.020-1.026 (27-35ppt). Use a refractometer to monitor salinity levels accurately.
• Ammonia, Nitrite, and Nitrate: Ammonia and nitrite levels should be undetectable, while nitrate levels should be kept below 20 ppm. Regular water changes and proper filtration will help to achieve this.
• Water Flow: Moderate water movement is ideal. This is most often achieved by using powerheads in the aquarium to move water around. Adequate water flow helps push uneaten food and fish waste into your filtration and also keeps the water oxygenated.

Diet

Yellow Assessors are Carnivores, meaning they rely on meaty foods for their nutrition. This fish isn't typically a picky eater and will accept food in a variety of forms. 

Primary Diet

• Frozen Food: They are small plankton feeders so foods such as brine shrimp, krill and mysid shrimp are perfect.
• Pellet Food: High-Quality pellets are a great option. Assessors prefer to feed in the water column, rather than at the water surface, so neutrally buoyant or slow sinking pellets work best. Pellet foods are typically very nutrient dense, so care should be taken to avoid overfeeding the aquarium, which can contribute to poor water quality.
• Flake Food: Flake food isn't as popular of a choice among saltwater aquarists, but if you opt for a flake food, be sure to choose a marine-specific option that's formulated to meet the needs of saltwater fish.

Feeding Frequency

Feed your Yellow Assessor at least once a day. For optimal health, try to offer small, frequent meals throughout the day-- 2-3 times is ideal if you can manage it. Your fish will probably always look hungry, so it can be hard to stop yourself from adding more food to the tank.

Compatibility

When it comes to tank mates, the Yellow Assessor is considered semi-aggressive and should not be kept with timid tankmates that are susceptible to being bullied.

Common Tank Mates

Here are some ideal tank mates:

• Fish: Clownfish, Gobies, Damselfish, most Wrasse, Tangs, Rabbitfish, Dwarf Angelfish, and other peaceful fish.
• Invertebrates: Assessors won't bother most invertebrates, so Cleaner Shrimp, Hermit Crabs, Snails, Urchins, and more are all safe to keep.
• Coral: The Yellow Assessor is considered Reef Safe and can be kept with Soft, LPS, or SPS coral.

Behavioral Notes

• Territoriality: The Yellow Assessor can be territorial in the aquarium, defending the area around its claimed space.
• Group Behavior: As a rule of thumb, only one Assessor should be kept per aquarium. In large aquariums, keeping pairs or trios can be successful, but is only recommended for experienced aquarists.

Acclimation Process

Acclimation instructions are included in each box, but if you misplaced yours or want to know what to expect ahead of time, you can always find an extra copy here: Fish Acclimation Instructions