Green Terror Cichlid: Tank Size and Care Essentials

Green terror cichlid (lat. Andinoacara rivulatus) is a very bright colored cichlid of the Cichlidae family. Despite its scary name, it has been a tank fish for many years. Further in the article, you’ll know about proper keeping, feeding, choosing tank mates for green terror cichlid.

Habitat in the wild

The Green Terror (Andinoacara rivulatus) belongs to the Cichlidae family. Cichlids are a diverse family of freshwater fish known for their colorful appearance, territorial behavior, and complex social interactions. They are popular among aquarium hobbyists due to their vibrant colors and interesting behaviors.

Green terror cichlid was first described by Albert Karl Ludwig Gotthilf Günther in 1860. As for the classification of this kind, it hasn’t been finally established yet. For a long time, this kind was considered Aequidens kind, though it was obvious that fishes are not similar. Because of this, it became necessary to separate the fish as a standalone kind which happened in 2009. Its specific name originated from Latin «rivulus» — a stream, and it is translated as «streaming» meaning wave-shaped turquois dashes and spots on the fish head and gill covers.

The fish inhabits in South America: in river basins in the West of Ecuador and Central Part of Peru. In the wild, they inhabit slow-moving or stagnant waters, such as rivers, streams, and ponds, with rocky bottoms and plenty of hiding spots among submerged vegetation, tree roots, and rock formations. They are often found in areas with a lot of aquatic plants and submerged branches.


The Green Terror has a relatively elongated and laterally compressed body, typical of many cichlid species. As it matures, the body may take on a more robust appearance, especially in males. Green terror males are larger than females, and they have an elongated dorsal and pectoral fin, pronounced orange stripe on the fluke edge (some species have an orange stripe up to 1 cm wide), and the stripes pattern on their face is more consistent.

The main coloration of the Green Terror is a beautiful green hue, which can vary in intensity depending on the fish’s mood, age, and environment. The green color is often accented with blue markings, especially on the face, dorsal fin, and anal fin. The body glitters with blue and green metallic, the dorsal and fluke have an orange line on the edges, the face is patterned with stripes and spots of blue and green color.

How big do green terror cichlids get?

It is a large and heavyset fish, and in the wild green terror cichlid, the max size is about 12 inches (30 cm). In a tank, the fish is usually smaller – about 8 inches (20 cm). However, in some cases, they can grow even larger, up to 12 inches (30 centimeters) or more in length.

How long do green terrors live?

Green Terror Cichlid have a relatively long lifespan compared to many other aquarium fish when provided with proper care. On average, they can live for approximately 10 to 15 years in a well-maintained aquarium environment. However, with exceptional care and a healthy environment, some individuals have been known to live even longer, sometimes reaching up to 20 years or more.

Green terror cichlid vs Blue Acara

This kind is often mistaken for another very similar fish – Aequidens pulcher. There were times when these two fishes were considered as one kind. However, nowadays, they were divided into two different kinds. Although the fishes are alike, they have some significant differences.

Green terror is a rather large fish, and in the wild, max size can be about 30 cm, when blue acara max size is just about 20 cm in the wild. The reproductive green terror cichlid male has a rather visible rounded hump on its head, whereas blue acara male hump is rather less pronounced. Also, green terror cichlid is rather more aggressive than the blue acara.

Scientific NameAndinoacara rivulatus
Common NameGreen Terror Cichlid
OriginSouth America (Ecuador and Peru)
SizeUp to 12 inches (30 cm) in length
Lifespan10 to 15 years or more in well-maintained aquariums
ColorGreen, blue, and iridescent colors
TemperamentTerritorial and can be aggressive, especially during breeding
Tank SizeA 75-gallon (284 liters) tank or larger is recommended for a pair of adults
Water Temperature22°C to 28°C (72°F to 82°F)
pH Level6.5 to 8.0
HardnessSoft to moderately hard water (4-15 dGH)
DietOmnivorous, will eat both meaty and plant-based foods
HabitatSlow-moving or stagnant waters, rocky bottoms, and abundant hiding spots
Tank SetupSubstrate of fine gravel or sand, plenty of rocks and caves, and some hardy aquatic plants
Breeding BehaviorMaternal mouthbrooders, females carry and protect eggs and fry in their mouths
CompatibilityCan be kept with larger, robust cichlids but avoid small, timid tankmates
Special ConsiderationsMaintain good water quality, provide a balanced diet, and observe interactions with tankmates
Conservation StatusNot evaluated (as of my knowledge cutoff in September 2021)

Difficulties in keeping

Although it is a very beautiful fish that attracts aquarists, it still can’t be recommended for beginners. Green terror is a large, aggressive fish, and to keep it in a tank, it has to be rather spacious.

The couple can terrorize its tank mates, and they should be of the same size and the same aggressive temper. Besides, the fish is rather sensitive to water parameters and their abrupt change. Due to these facts, fish can be recommended only to the aquarists experienced in keeping large cichlids.

However, beginners can also take care of green terror cichlid successfully, but only if they can create the proper conditions and choose proper tank mates.

Like many large cichlids, they are very smart. During the time, they learn to recognize their owner and let him touch them. Also, they are not timid, and when someone approaches the tank, they gather near the front wall and see who is there, and this feature allows observing them without risking scaring them.

Care and keeping in a tank

Care is rather easy since it isn’t a very demanding fish. But still, it’s recommended for experienced aquarists since the fish is demanding in terms of water parameters, and it requires qualitative food.

Tank size

Just like all South America large cichlids, green terror cichlid requires a spacious tank with clean water. Also, as it is always true for the large cichlid – this one is rather large and aggressive, it needs a spacious tank. While green terror is young, it can successfully grow with other cichlid fish, but as it grows, it becomes more aggressive, and it’s better to keep the fish with tank mates that are aggressive and large, too.

For a single adult Green Terror, a minimum tank size of 75 gallons (284 liters) is recommended. However, keep in mind that larger tanks are always better, as they allow the fish more room to swim and establish territories.

For a fish couple, consider a tank size of at least 100 gallons (378 liters) or more. In case if there are some tank mates, the tank size should be larger correspondingly. When adding tankmates, ensure that the tank is large enough to accommodate the additional fish while also providing ample space for the Green Terrors to claim their territories.

A larger tank not only reduces aggression but also helps maintain water quality, as larger volumes of water are more stable and dilute waste products more effectively.

Water parameters

Maintaining suitable water parameters is essential for the health and well-being of Green Terror Cichlids. These fish are relatively hardy, but maintaining stable and optimal water conditions will help reduce stress and potential health issues.

Here are the recommended water parameters for Green Terrors:

  1. Temperature: 22°C to 28°C (72°F to 82°F). The ideal temperature range is between 24°C to 26°C (75°F to 79°F). They can stand short-term water temperature decrease up to 64 °F (18 °C), but we don’t recommend exposing them to such stress.
  2. pH Level: 6.5 to 8.0. Aim for a slightly acidic to slightly alkaline pH. A pH level around 7.0 to 7.5 is generally suitable.
  3. Water Hardness: Soft to moderately hard water. The general range should be between 4 to 15 degrees of hardness (dGH).
  4. Ammonia and Nitrite: Both ammonia and nitrite should be at undetectable levels. Ammonia and nitrite are toxic to fish and can lead to health problems or even death.
  5. Nitrate: Keep nitrate levels as low as possible, ideally below 20 ppm (parts per million). Regular water changes are essential to control nitrate buildup in the aquarium.

Tank setup: decorations and plants

The tank should be moderately lighted, and the tank design should be typical for large cichlids – rocks, snags, and gravel bottom. In addition to the tank size, providing hiding spots, caves, and ample places to establish territories is essential for these territorial cichlids. Including rocks, driftwood, and live or artificial plants will help create a more natural and enriching environment for your Green Terrors. Always monitor the fish’s behavior and consider their needs when planning their habitat. Provided with proper tank decoration with plants and other decorative elements, it may look awesome with just one couple of green terror cichlid in it. The interesting fish’s behavior more than outweighs their quantity.

Unlike other cichlids, these don’t include plants in their diet. However, they tend to dig them out, especially during the spawning period. Thus, you should select undemanding stiff-leaved plants with a strong root system. Plants of Echinodorus kind and some of Anubias kind will do for this. It’s better not to put plants in the tank since fishes tend to dig the tank bottom and change it according to their preferences.

After planting, they should be additionally fixed with large flat stones. You can put plants in containers this way, and you significantly decrease the chances of digging them out. Large stones and snags are obligatory decorative elements for a tank with cichlids. One of these flat stones in the tank corners may later be used as a substrate for spawning.

Such a tank interior with the decorated back wall has a maximally natural look. It is possible to use artificial plants. The main thing is that all tank decorations are reliably anchored. Because the fish is always not satisfied with the interior and continuously changes it.


Considering green terror cichlids’ passion for digging substrate, the latter should consist of small-sized round pebbles so they won’t get cut by sharp edges. Usually, gravel or large/average-sized pebble are used as a substrate.


Provide efficient filtration to remove waste and debris from the water. Green Terrors are sensitive to poor water quality, so a good filtration system is crucial. It’s obligatory to use a powerful canister filter and to control nitrates and ammonia levels in the water. It will allow not only to collect various suspended matters from the tank water but also to avoid a high concentration of toxic substances of nitrogen metabolism in the tank due to the life-sustaining activity of useful nitrifying bacterias.

Regular partial water changes, typically 20-25% of the tank volume, should be performed weekly or bi-weekly to maintain water quality and remove accumulated pollutants. Remember that sudden and significant fluctuations in water parameters can be stressful for fish. When performing water changes, try to match the temperature and pH of the new water to that of the aquarium to minimize stress on the Green Terrors.


Green terror diet in the wild mainly consists of insects and their larva, worms, and other spineless species. In general, the fish isn’t demanding, and in the tank conditions, they eagerly eat all types of food, both live, frozen, and artificial. Many aquarists feed adult green terror fishes with non-fatty sea fish and prawns. Offer live or frozen foods such as brine shrimp, bloodworms, daphnia, and mysis shrimp. These foods are rich in protein and help simulate the variety they would encounter in their natural habitat.

You should feed them several times a day. Hungry fish may demonstrate prey drive and attack their tank mates.

To select the food properly, you should keep in mind that green terrors are predators, and they require significant protein components in their diet. The food size also must be proper since large adult species have quite a large mouth.

Quality dry food for cichlids is a good choice in this case. Food made as large floating sticks is best for adult species. They stay on the water surface for a long time, and their shape resembles the food the fish eats in the wild. Well-balanced food boosts their natural coloring, vital power, and immunity. It’s better to feed juveniles with flakes or small pellets. Look for high-quality cichlid pellets or flakes specifically formulated for South American cichlids. These should be a staple part of their diet and provide essential nutrients.

Tank mates

Space is a crucial thing for all large American cichlids. Besides, it is in the spacious tank where their level of aggression decreases. Green terror is a rather battlesome fish that will provoke its tank mates itself. However, it all depends on the fish temper and tank conditions.

Some fish, when reaching their reproductive stage, become more peaceful. The same is about the green terror family – it is recommended to keep one fish couple in a tank to avoid fights. Often female is more aggressive than the male, and she is sometimes kept separate from others. During the spawning period, the fish gets completely crazy, and it’s better to keep them apart from each other.

You can’t keep green terror cichlid with small African cichlids and with angelfish since the latter will either be killed or stressed all the time. It’s better to use the following fishes as green terror cichlid tank mates: oscar, jack dempsey, arowana, convict cichlid, flowerhorn, blood parrot, jaguar cichlid, texas cichlid. You can keep it with some large catfishes, for example, sailfin pleco or suckermouth catfish.

First of all, all fishes sharing a tank with green terror cichlid should be of similar size. Any small-sized species (even average-sized ones) will be eaten sooner or later. In a perfect world, if green terrors and their tank mates live in a community tank since they are juveniles and grow together, this will ensure a decrease in their aggression.

The tank must have many various shelters for its dwellers, and its volume should be enough for large fishes to live.

During their spawning period, they become aggressive towards their tank mates. If a male or a female started to prepare a nest for laying eggs, anyone who approaches it would be immediately attacked.

Gender differences: male vs female

Green terror male and female don’t have many differences. Distinguishing between male and female Green Terror Cichlids can be challenging when they are young and not yet sexually mature. However, as they reach maturity, there are some observable differences that can help identify their gender. Keep in mind that these differences may not be definitive in all cases, and there can be variations between individual fish. Here are some general characteristics that may help you differentiate between male and female Green Terrors:

Male Green Terror:

  1. Coloration: Male tend to display more intense and vibrant colors, especially during breeding or when they are in prime condition. Their green and blue coloration may be more pronounced.
  2. Fins: Mature males often have longer, pointed dorsal and anal fins compared to females. The dorsal fin may also have more extended filaments.
  3. Body Size: Males may grow slightly larger and have a more robust appearance, especially around the head region. Some males may develop a noticeable nuchal hump on their forehead, particularly during breeding.
  4. Behavior: Male Green Terrors can be more territorial and aggressive, especially during the breeding season when they are protecting their territory and fry.

Female Green Terror:

  1. Coloration: Females may have slightly less intense colors compared to males, especially when not in breeding condition. They may appear more subdued but can still display beautiful green and blue hues.
  2. Fins: The dorsal and anal fins of females are generally shorter and may not have the extended filaments seen in males.
  3. Body Size: Females may be slightly smaller and more streamlined compared to males, but this difference may not always be very noticeable.
  4. Behavior: Females can also be territorial and protective of their young, but they may show less aggression than males during breeding.


Breeding isn’t a complicated thing. The couple is formed rather easily by random matches, that’s why you can buy future breeders from different owners, and they can be already adult fishes. This allows avoiding inbreeding. If the fish couple doesn’t do well, it’s better to change a female fish. A united fish couple is preferable for breeding and keeping.

The references mentioned that green terror spawning is stimulated by raising the water temperature and water renewal. Actually, it’s not required in real life. Provided with good conditions in a tank fishes spawns regularly. The problem is the opposite – how to decrease the frequency of spawning.

Chemical water parameters also don’t affect the situation a lot. Male and female choose a substrate good for breeding and start cleaning it. In the absence of the rock they like, the fishes can clean the bottom from the sand and lay the eggs right on the tank bottom glass. Breeding color becomes more colorful. Blue splotches become fluorescence. Along with the bottom cleaning, the fish also prepares some pits in the bottom where they will hide their ich fry later.

It usually spawns in the evening or early in the morning. The female lays the eggs when moving over the rock surface, and its trajectory looks like digit “8”. The male follows the female and fertilizes the eggs. Usually, there are about 200-300 eggs in one clutch, but if the female is large, there can be about 1000 of them.

Healthy fertilized eggs have a yellowish color, and they are semi-transparent. Both parents take care of the eggs. The female fish waves over the eggs with her fins, and the female guards the territory from strangers. It becomes aggressive during the spawning period and attacks any moving object – fishes, net, or hand.

However, sometimes it happens that parents don’t take care of their eggs or eat either the eggs or fry. The breed of such fishes should be incubated separately: carefully move the rock with eggs out of the tank and move it into an incubator – another small separate tank with the same water parameters. The sprayer is put above the eggs.

The eggs that became white should be removed with pincers. The time of the egg germination is 3-4 days, and ich fry germination time is 2-4 days. After ich fry appears, the female takes it into one of the pits in the tank bottom they prepared in advance. Juveniles are quite large, and they have a good appetite. Start food for juveniles is brine shrimp nauplii, mycoplankton or its artificial substitute, egg yolk, etc.