Lunar Beauties: Moonlight Gouramis Trichogaster microlepis

Author: Maddy Hargrove

With a silver body so iridescent that it seemingly glows, this gourami makes the perfect choice for aquarists wishing to add a sense of the celestial to their tanks.

Overlooked Beauties

Often overlooked by hobbyists and dealers and not always available in aquarium shops, the beautiful moonlight gourami Trichogaster microlepis can instantly transform your home aquarium into a wondrous scene. Their graceful swimming through the planted waters of a large tank makes for a truly awesome sight. Even in low lighting, this fish’s unique color scheme allows it to shine above the rest. All things considered, moonlight gouramis are undeniably gorgeous.

T. microlepis is a labyrinth fish from the family Osphronemidae. Native to Cambodia, Thailand, and Vietnam, it has also become established as an alien introduction in other areas in Asia and in Colombia, South America.

These gouramis can be found hanging out in the thickly vegetated, shallow-standing waters of ponds and swamps in their native habitat. Locals in these areas often eat moonlight gouramis as a regular part of their diet. Hobbyists have thankfully found a better use for this marvelous fish in the home aquarium. This species was first described by GÜnther in 1861 and is known by different names, including moonbeam and moonlight gourami.

Moonlight Basics

Appearance

The moonlight gourami has a silver-colored body that casts a slightly greenish hue, giving it the appearance of being under the soft glow of the moon. This green becomes increasingly iridescent as the fish matures to an overall length of 5 inches.

T. microlepis has a compressed, rather elongated body, and the concave slope of its head distinguishes it from other gourami species. It also is unlike most other gouramis in having a single—but iridescent—body color without markings of any kind. Younger gouramis lack the green and silver iridescent hues of their adult counterparts, but they will reach their full, brilliant coloration as they mature.

Males vs. Females

The males of the species will develop an orange/red color in their pelvic and dorsal fin, which comes to a point near the end. The females have a light yellow tint in their pelvic fins, and their dorsal fin is rounder and shorter than the males. The anal fin that extends along the length of the belly to the base of the tail has a beautiful pastel green sheen in both sexes.

Colorful Irises

Another interesting feature of the moonlight gourami is the red or orange irises, which are quite conspicuous. They have an effect similar to those evoked by old paintings featuring eyes that seemingly follow your every movement.

Ventral Fins

The ventral fins are very long and shaped into narrow filaments. They are similar to those found in other gouramis but are much longer. The fins contain sensory cells that help them navigate and locate food. These filaments give the moonlight gourami a unique, delicate appearance as they float gently in the current. During spawning, the ventral fins on the male will intensify in color and become a deep red that helps them impress and attract potential mates.

Breathing

Like all labyrinth fish, the moonlight gourami has a special lung-like organ that allows it to breathe air directly from above the water line. It is common to see this species slowly move toward the top of the tank and gulp air above the surface. Despite the fact that this organ allows moonlight gouramis to survive in pools with a low oxygen level in the wild, they still do best when placed in tanks with proper filtration and excellent water quality.

Feeding

Moonlight gouramis are omnivorous and not picky, which make them very easy to feed. This species will readily accept flakes, frozen foods, and live foods. Favorite treats include bloodworms, brine shrimp, insects, and small crustaceans. Diet should be varied to ensure that the fish remain in optimum health. If fed, cared for, and housed properly, this species can live for many years in a home aquarium.

When your gouramis are in a community setting, larger, quick-swimming fish can scare them away from their food, but they can generally hold their own, and they may in turn chase smaller fish from food.

Aquarium Conditions

Tankmates

Be sure to exclude tankmates that are fin nippers from the gourami’s aquarium. Their long fins are just too tempting as targets. Good tankmates are medium size, peaceful fishes, but make sure they are not too small or your gouramis will pick on them.

Tank Requirements

The moonlight gourami is a top- to middle-level dweller. The tank should be large because they need plenty of swimming room, and a dark substrate will help show off their amazing coloration.

Moonlight gouramis enjoy a very slow water current (so they don’t get blown around the tank) and warm water. They are quite adaptable about water chemistry, but the temperature should be warm, kept between 77° and 86°F. These fish are best displayed in subdued lighting.

Staying active with tank maintenance (including regular water changes) is very important for this species for maintaining their health over the long term. They are pretty hardy as far as fish go, but if you really want them to shine, keep the tank conditions perfect. Set up a good weekly maintenance routine so you can keep on top of their needs.

Males and Females

Like most other gouramis, these are best kept as a single male with one or more females. If you plan on keeping multiple males, the aquarium should be large enough so that each male will be able to establish his own territory. As gourami males age, the territoriality instinct tends to increase. The good news is that the females are usually more sedate than the males.

Plants

Moonlight gouramis should be kept in a large, heavily planted aquarium with floating plants, which is where the male will anchor his bubblenest. Live plants will also provide hiding places and a sense of security, and they show off the fish very well.

Unfortunately, this species will chew on most aquarium plants as a snack, and very fine-leaved plants will be damaged quickly. A good compromise for the moonlight gourami is to plant the aquarium heavily with thick-leaved, hardy plants, such as Java fern, Vallisneria, and Anubias. But if you are looking to maintain a prize-winning planted aquarium, this is not a good species to keep, as they will still nibble the greenery.

Breeding

Breeding moonlight gouramis is relatively easy. Ideally this species should be provided with a separate breeding tank, as other fish in your aquarium will consider eggs and fry an ideal source of food.

Breeding Tank

The breeding tank should have slightly soft water, a simple sponge filter, and the temperature should be raised to at least 80°F during spawning and rearing. Floating plants are beneficial to give your moonlight gouramis a feeling of security and to anchor the bubblenest.

Spawning Process

If you feed the breeding pair live foods before attempting the breed them, that will greatly increase your chances for success by encouraging them to spawn. Gouramis are egglayers. The male moonlight gourami begins the spawning process by carefully preparing a bubblenest, which he makes by blowing bubbles out of his mouth. The bubbles have a coat of saliva, which helps them stick together.

The male will then begin to relentlessly court the female by performing a lively courtship dance on her behalf. Once the female accepts him, the spawning begins: The male carefully wraps himself around her, and while wrapped in this embrace, the male will gently turn the female on her back, which encourages her to release eggs.

The eggs are fertilized in the embrace, and the male picks them up in his mouth and blows them into the nest, making sure they are all safely secured within the bubbles. You can provide the female a safe haven after spawning by adding bushy plants to hide in if the male becomes aggressive. Generally this species is easier on their mates than some other labyrinth fish, such as bettas.

Eggs and Fry

The eggs will incubate for about two to three days before finally hatching into young fry. The male will guard the nest and return fry that fall out until the babies become free-swimming. At that point he should be removed.

Once the fry are free-swimming, they must be fed. They are very tiny and require suitably small food. Tiny live foods like paramecium and baby microworms are good, followed by daphnia, rotifers, and baby brine shrimp as the fry grow large enough for them. They can also be fed manufactured fry foods or ground flake food. Some breeders have success using green water as a first food source.

Magnificent Moonlights

If you are interested in setting up a beautiful tank with a species that you have never tried, you should give the moonlight gouramis a shot. Put them together with some of your favorite fish, and you’ll have a wonderfully relaxing aquarium scene that will always remind you of the pleasure of a quiet nighttime walk under a magnificent, silvery moon!

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