Minimum Tank Size: 20 Gallons (75 Liters)
Care Level: Easy
Water Conditions: PH 6.0-7.5 Soft to Moderately Hard
Temperature: 72-82°F (22-28°C)
Maximum Size: 2 inches (5 cm)
The lemon tetra (Hyphessobrycon pulchripinnis) is a small, fresh water fish and an old favorite among aquarists. These fish are native to Brazil, and were first collected for the aquarium trade in 1937 – making them among the oldest of modern aquarium fish.
Lemon tetras inhabit clear water, with a moderate current, and tend to dwell in the shallows near to shore. They are often found in heavily vegetated areas of narrow, overgrown streams, and this environment should be recreated as closely as possible in the home aquarium.
These fish stay relatively small, and grow to a maximum of 2 inches (5 centimeters). On average, they live for around 6 years in captivity, though well cared individuals can quite easily live for 8 years or longer.
Lemon tetras shoal in vast numbers in the wild, and they should be kept in large groups in the home aquarium. While they can be kept together in groups as small as six, they only really thrive when kept in groups of a dozen or more fish – with approximately equal numbers of males and females. There are rewards for keeping them in large groups though, as they are more likely to show off their colorful shoaling behavior.
Any aquarium containing these fish should have soft water, and should be heavily planted, but with open spaces left for swimming. In bare tanks, these fish will often lose their coloring. In the past, wild caught specimens lost their coloring in hardwater, but now that the majority of these fish are farm raised, they can adapt to most water types.
These fish do well in community tanks, and can be kept with most small species of tetras, barbs or corydoras catfish. They do especially well with other shoaling fish, and tanks set up with several groups of tetras can look truly stunning. Dwarf, non-aggressive cichlids also do well with these fish, though even with peaceful cichlids, aggression can sometimes become an issue.
A hang-on-back filter is usually the best choice for these fish, as it has the added benefit of adding some much-needed current to their tanks. I personally recommend Aquaclear Power Filters, which are both tough and long lasting. I use these filters on most my tanks, and they have been running problem free for years.
In the wild, lemon tetras primarily feed on invertebrates, crustaceans, and plant matter. But in captivity, these fish greedily accept nearly any food that is offered to them. Their diet should be comprised of a high quality prepared food, with regular feedings of live or frozen foods. An excellent choice for fish food is Hikari Tropical Micro Pellet Food, which was specifically developed for small mouth fish.
They should also be offered frozen or live foods, and their favorite live foods are black worms, daphnia, gut-loaded brine shrimp, blood worms and mosquito larvae (illegal to breed in some areas). Their taste is very similar in frozen foods, and they can be offered frozen bloodworms, blackworms and daphnia.
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It can be difficult to sex these fish while they are still juveniles, but it is quite easy to determine the sex of adult fish. This is done through examining the edge of the anal fin. In the male, the edge of the anal fin is quite wide, and when they are ready for breeding, it can take up almost 1/3 of the fin. Females on the other hand, have only a fine black line on the edge of their anal fins, sometimes barely visible.
Males also generally have brighter colors than the females, though this can be an unreliable way to differentiate them. Females do become more plump than the males when they become laden with eggs, but this is also an unreliable way to sex mature fish.
When a male is ready to reproduce, he will stake out a certain location in the aquarium and put on a display for rival males. While it may appear that males are fighting in these displays, they are ritualistic behavior, where neither fish is usually harmed. During these displays, the males will position themselves with their heads pointed slightly upwards, and their fins held out. They will then swim at each other, making passes, and trying to get as close as possible without touching the other male.
These displays can go on for up to 30 minutes, though they are usually significantly shorter. The females will often watch these displays, and they help to both advertise a male’s social status, and his breeding readiness.
Once the females are ready to breed, the males will chase them through the vegetation in the aquarium. It’s not unusual for several males to chase a single female through the tank, sometimes changing to another female mid chase.
The female will then move towards more dense vegetation, or other hidden areas of the aquarium with a male. Both will begin to flash their yellow fins, with the male in a head down position. After this, they will move towards fine leaved vegetation to mate – the female releasing her eggs over the leaves. Some of the eggs will be caught by the leaves, but others often fall down to the substrate.
Lemon tetras show little parental behavior, and most of the eggs will be consumed by the parents in the aquarium. For any eggs to survive, conditioned fish should be moved to an aquarium specifically setup for breeding.
The same setup used for zebra danios can be used for lemon tetras. The males and females should be separated and conditioned with live foods for several weeks. Once the females have become plump, a single male and female should be added to the breeding tank with marbles covering the bottom. The tank should also have fine leaved plants, a sponge filter to protect the fry, and soft, acidic water.
They should then be closely monitored, so that after they have spawned, the parents can be removed from the aquarium quickly. Most of the eggs should fall between the marbles – outside the reach of the hungry parents.
If they don’t spawn right away, the temperature should be raised until it’s around 79-84°F (26-27°C), which will usually trigger breeding. If that doesn’t work, then the light cycle should be steadily increased until they are getting at least 12 hours of light a day. Some aquarists report that sunshine in the morning will also help trigger breeding, though this hasn’t been extensively tested.
The eggs will usually hatch after 3-4 days, and the fry will become free swimming in 24-48 hours. After they become free swimming, the fry can be fed microworms, infusoria, or any of the commercially available fry foods. When they are close to a week old, they can then be moved on to baby brine shrimp.