FIA is community supported website. When you purchase through links on our site, we may earn an affiliate commission. Learn More.

Purple Firefish Goby Species Overview & Care Guide

The Purple Firefish Goby (Nemateleotris decora) is a small saltwater fish decked with varying degrees of white, yellow, and deep shades of purple.

Their docile nature makes them an excellent addition to any aquarium of a suitable size. The fun-going character and handsome appearance make it highly popular among fish owners.

You will learn about purple firefish care in the guide, including recommended diet, water condition, aquarium setup, joint disease, and other helpful information.

Species Overview

The purple firefish goby (Nemateleotris decora) are relatives of Nemateleotris Magnifica and have a unique shape and color that makes them highly sought after by aquarists.

The fish belongs to the Gobiidae family and is known for its peaceful temperament. Other names of the fish include Purple Dartfish, Decorated Firefish, Flame Firefish, and Decorated Dartfish. The species can survive for up to 3 years with proper care.

Natural Habitat

Purple Firefish Goby is found in the Pacific and Indian sea. The fish is commonly found in the reefs around Mauritius to Samoa, south to New Caledonia, and north to the Ryukyu Islands at depths of 82 to 240 feet.

Hiding Behavior

Juvenile purple firefish gobies are fond of hiding among rock works and corals—the coral reef used as a defense mechanism that protects them from larger prey.

The small size allows them to remain hidden from large predators. They are not territorial and remain nonviolent towards other fish. Instead of hunting, the fish face the current allowing the prey to come to them.


The Purple Firefish Goby has a slender appearance with a single raised fin behind its head. The front of the fish is white, while the hind region is purple.

Their dorsal fin has 7 spines and around 32 soft rays that they can erect when threatened. It alerts other fish and a locking device that locks to an aperture similar to the triggerfish.

The purple Firefish goby also has a swim bladder. The unique structure allows the fish to hover in one location for long periods with the face pointed upwards. This movement is valuable in detecting predators in the wild.

Gender Differences

Males and females are of the same size. There is no discernible difference between the two. It creates incredible difficulty when it comes to breeding fish.

You cannot know about the gender of the fish. The five or six fish you have bought from the store may all turn out to be males.

Males are not only aggressive towards other males and also female goby fish. It adds to the difficulty in determining the gender of the fish.

Behavior & Temperament

They are not territorial or aggressive. The fish is gregarious and calm. It is compatible with a large number of fish, making it ideal for community aquariums.

In the wild, the Purple Firefish swims in water currents near the reef’s heads, where they feed on planktons. In the native waters, several juvenile goby fish share the same place. But adult fish are generally territorial that don’t tolerate other fish, even of the other gender.

Adult Purple Firefish need a minimum 20-gallon enclosure. They will form a hierarchy of dominance inside the aquarium, similar to a hen’s pecking order. Adult healthy fish will dominate smaller and weaker fish.

The smaller and weaker Purple Firefish will respect the alpha fish’s command staying away from its path.

Purple Firefish has a peculiar behavior of flicking the first dorsal fin back and forth when swimming. Like most Gobiidae family members, it stays exceptionally close to their hiding spot, swimming around the rocks and crevices.

Purple Firefish will tend to seek out unused areas inside the aquarium. They tend to claim empty large caverns or overhangs as their home. If there are no caverns or rocks, the fish will swim to the lower half of the aquarium.

If the fish becomes stressed, they tend to jump out of the aquarium. The fish usually become stressed when due to low water conditions.

They are timid and feel threatened by larger fish. It will force them to spend most of their time hiding and reduce their lifespan. If larger fish harass them, they will become stressed and try to jump out of the aquarium.

The Purple Firefish will hide in the tank for days once introduced into the aquarium with other fish. It makes some owners think that the fish has disappeared.

But the fish will reappear once it feels comfortable with the more contemporary surrounding. Once the fish overcome their timidity, they will chase small food scraps from other fish inside the aquarium.

The fish are generally gregarious and friendly with other fish. They are also non-aggressive fish that won’t harass other fish.

Tank Mates

Purple Firefish can be kept in a fish community in a small aquarium. They are not territorial and aggressive which makes them compatible with other peaceful fish.

It would help if you considered keeping them with small fish. Larger fish might treat the fish as food and devour them.

Fish that are not compatible with Purple Firefish include pufferfish, triggerfish, lionfish, butterflyfish, batfish, wrasses, and sweetlips.

They are also not compatible with eels since both like to swim through small holes and rocks. If you want to keep them together, you should make sure that there are plenty of rocks and other hiding places.

Tank Mates which include

  • Juvenile Clownfish
  • Peaceful Tangs
  • Basslets
  • Surgeonfish
  • Wrasse

Smaller fish like benthic fish are also an ideal mate for fire goby fish.

Purple Firefish is an excellent choice for a reef aquarium. They don’t pick at corals or bother other fish. The fish like to spend most of the time swimming above the coral reef to feed on plankton. The small fish can also not bother invertebrates, including ornamental shrimp.

When picking mates for the Purple Firefish, you should not select species of the same group. They are aggressive towards conspecifics.

Ideal Aquarium Conditions

Purple Firefish are sensitive to water conditions. You should make sure that the water temperature inside the aquarium is between 72 °F-78 °F. The water should be alkaline with a pH between 8 and 8.4 since they are a saltwater species.

Water should be kept clean at all times. Low quality and dirty water can increase the stress that reduces the immune system of the fish.

You should change about 15 percent water after every two weeks for 30 gallons of the aquarium. For larger tanks above 30 gallons capacity, you should change about 30 percent water once a month.

Keeping the pH value to the desired level is necessary. The pH levels should be maintained using water changes rather than using chemicals. You must use proper testing equipment to check the pH level and nitrate or ammonia level inside the tank.

Aquarium Setup

Purple firefish looking at camera

Purple Firefish require a medium-sized aquarium of at least 20 gallons. The fish will not attack other fish but will be aggressive towards their species if kept in a small tank.

The tank should be wider instead of taller. The aquarium should contain a coral reef. They also require lots of hiding places with plenty of crevices within rocks and caves. But avoid sharp rocks that can damage the body or long fins of the fish. Feeding Purple Firefish Goby

Purple Firefish Goby are carnivorous and eat a large variety of meats. They prefer to eat brine shrimp, Mysis, shrimp, finely chopped and frozen seafood, and zooplankton.

Ensure only to utilize high-quality foods for these fish because they can quickly lose their attractive colors depending on their diet.

You can also give frozen food formulas that are available at most pet food stores. Gut-loaded brine shrimp and foods enriched with vitamins are some of the best choices if you want your purple Firefish to maintain their intense purple hues.

For the most part, you shouldn’t face any difficulty feeding them. It can be an entertaining sight to see. Quickly strike at the food that floats near and often hunt for leftover scraps near the substrate.

Put food directly in their face if tank mates prevent the food from ever reaching the bottom of the aquarium.

Purple Firefish Goby are quick swimmers and should not have much trouble in getting the food. However, they become timid when feeding with larger fish. Avoid placing the fish with larger fish.

But if you want to place them with larger fish, you should keep an eye out to ensure that the fish is feeding correctly. Consider spreading the food throughout the tank so that the fish has a chance to provide it.

You should avoid overfeeding the fish as that may make them susceptible to various diseases. Consider feeding them as much food as they can eat in about six minutes. It will help if you spread out the feeding two to three times a day.

Breeding Guidelines

It wouldn’t be easy to determine the gender of the Purple Firefish goby if bred in captivity. But once you’ve formed a Purple Firefish pair, all you have to do is meet the right conditions for high hatch rates.

The best part is that you can raise juveniles in the same tank they were red in because they guard both the eggs and the fry.

To initiate breeding, raise the tank’s temperature to around 85° Fahrenheit and ensure that the pair has a stable environment with no threat from trespassers.

They must have a stable feeding schedule with food that reaches both Purple Firefish Goby. If the pair were competing for food, they would not mate since half the time they’ll be chasing each other for food scraps.

Please provide them with a light schedule of 10 hours of darkness and 14 hours of light. Courting and spawning will take around six months, and the total egg count will be about 500 eggs per spawning.

You’ll see that 90% of the eggs will hatch after about 100 hours. They fed on zooplankton and phytoplankton. Increase their food portions as they grow in size. On day 40, the fry grows large enough to be seen as juveniles.

Purple firefish pair

Common Diseases and Treatment

Purple Firefish Goby are resilient and hardy. They don’t succumb to illnesses unless the water quality is low. The fish may also become ill if they stress inside the aquarium.

A diseased Purple Firefish Goby may sometimes have marks or sores. A bacterial infection often causes this illness. The fish may also act out strangely and may appear to be lethargic. Aquarists have success in treating the condition using Furan medication such as Nitrofurazone.

It would help if you gave a total dose of the medication in a separate tank. Make sure that there is plenty of aeration in the aquarium used to quarantine the fish.

Avoid feeding the goby fish when medication is going on. It will make the water toxic which will cause more severe health issues. Using erythromycin and tetracycline has also been found to be effective against the disease. It would help if you used the total dose; otherwise, the infection might reappear and be difficult to treat.

Similar to other saltwater fish, purple firefish goby is also prone to protozoan and parasitic diseases. You should ensure that the water remains clean at all times.

Aquariums need plenty of decoration items to ensure that they don’t get stressed out. A stressed Purple Firefish Goby is more likely to get a disease due to low immune systems.

Keep the fish happy by feeding appropriately and changing the water regularly. It will ensure that the fish lives for a long time.

You should also closely monitor the water conditions and clean the water at regular intervals. The fish will rarely become ill if you take great care in keeping the water clean and compatible with the fish.

Purple Firefish Goby Care Tips

Feed Purple Firefish Goby a nutritious diet so that they remain healthy and happy. It would help if you considered giving them a variety of food items. Consider mixing the food items to ensure that they get the most nutrition from food.

Remove uneaten food items inside the aquarium after about an hour. The food items will break down over time, resulting in excessive waste.

Another concern is getting them to eat when they are in quarantine. The fish will reject most food as it will be stressed out when kept in quarantine due to disease or when introduced to the aquarium.

It would help if you enticed the stressed fish to eat by giving gut-loaded feeder shrimp or frozen food mixed with sponge pellets.

Frequently Asked Questions

Are these reef safe?

Purple Firefish are reef safe. The fish won’t nip and kill the corals. The fish will not eat soft corals and also corals with large polyps. It, too, won’t eat invertebrates such as snails, shrimp, and crabs. So, you can safely add the fish to your coral aquarium.

Are these hardy?

For the most part, Purple Firefish is the ideal choice for beginners new to marine fishkeeping because they are incredibly sturdy and forgiving for things like water parameters and diet.

You can feed them most fish foods (carnivorous diet), and as long as you don’t deviate too much from the recommended care requirements, your Purple Firefish should remain free of disease for the duration of their lifespan.

Where to buy?

You can find Purple Firefish Goby for sale in most online stores. They are mostly available in pet stores in small sizes. Before introducing the newly bought fish to the aquarium, you should quarantine them for a few days to ensure that they are healthy.

Ask about the diet fed to the fish. It would help if you bought from a store that has properly fed them on a steady diet of high-quality meaty foods. It is essential since a fish fed with meat-based food will reject all other food. The result will be less healthy fish with a reduced lifespan.

Purple Firefish Goby is sold when they are small. Juvenile fire goby are more likely to jump when stressed due to the new environment. It would help if you kept a tightly fitting lid with holes covered to prevent the fish from jumping out of the aquarium.

Make sure to tape areas around the heater power cord, filtration, and overflow box. The fish will not jump as they grow and become accustomed to the new environment.

Wrapping Up

Purple Firefish Goby is a colorful fish and a joy to watch inside the aquarium. They are easy to care for and don’t have special nutritional requirements. It makes the fish suitable only for beginner aquarists.

But the water parameters and feeding guidelines must be followed so that the fish remains healthy.

Purple Firefish Goby are peaceful fish that make it easy to match tank mates. You can keep them in a small aquarium with other similar size fish. Taking care of the fish is not demanding. The alluring appearance and attractive personality make them perfect for reef and regular aquariums.