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Multies live in large colonies in the shell beds left by the lake's native Neothauma snails. This natural shell bed habitat is what the aquarist should be aiming to replicate when setting up an aquarium for Neolamprologus multifasciatus.

Neolamprologus multifasciatus

N. multifasciatus male
N. multifasciatus male

Several species of dwarf African cichlids make their homes in shells. Collectively, they are known as Shell Dwellers. The species that I keep is Neolamprologus multifasciatus, often referred to as "Multies". These fish come from the sandy, rocky bottom near the shores of Lake Tanganyika in Africa. Multies live in large colonies in the shell beds left by the lake's native Neothauma snails. This natural shell bed habitat is what the aquarist should be aiming to replicate when setting up an aquarium for Neolamprologus multifasciatus.

Lake Tanganyika

Lake Tanganyika from Space - NASA Image
Lake Tanganyika from Space - NASA Image

Lake Tanganyika is fascinating for a variety of reasons. It is the largest of Africa's rift lakes, the second deepest lake in the world, and it holds about 16% of the world's available fresh water. Tanganyika is home to at least 250 species of cichlids, plus other fish that are not part of the cichlid family. It is also home to dozens of species of freshwater snails and bivalves. The water in Lake Tanganyika is notoriously hard and alkaline. The PH is about 9.0, and the water is very high in calcium. Temperatures at the surface range from 75 to 84 degrees (F).

Setting up a Tanganyikan Shell Dweller Aquarium

Multi tank
40 gallon Multi tank

Aquarium Size for Shell Dwellers

N. multifasciatus are small cichlids: the largest males may reach 5 centimeters, while females usually top out at 2.5 cm. This diminutive size makes them a good choice for a smaller aquarium. The minimum tank size I would recommend is 10 gallons. Anything smaller will be subject to rapid fluctuations in water parameters. A 10 gallon tank could hold 1 or 2 breeding groups (6-12 fish). Use a 20 gallon long or similar high surface area format tank to show off their colony breeding behavior. Personally I keep them as the only species in a 40 gallon breeder. The large surface area provides space for about 60 shells.

Substrate for Shell Dwellers

To see Multies at their best, the aquarist should aim to recreate the conditions of their ancestral lake. Start with a relatively deep sand substrate, mixing in crushed coral or aragonite to ensure there is plenty of calcium present to keep the water buffered and the PH high. N. multifasciatus are diggers. They pick up sand in their mouths and spit it out, building hills and burrying their shells so that only the entrance is visible. I recommend a substrate depth of 2-3 inches to give them plenty of space to dig.

Snail Shells for Shell Dwellers

Neothauma Mollusks
Neothauma Mollusks

Of course, one of the most important additions for shell dwellers is the shells! In the lake they live in the discarded shells of Neothauma snails. But these snails are only endemic to Africa and the export of their shells is tightly controlled. If you are able to find legitimate Neothauma shells, expect to pay a high price. Instead, most Multi keepers use escargot shells that are commonly sold for cooking. They are very close in size to the Neothauma shells and very affordable. You will want 1 shell per adult fish, keeping in mind that these fish live in colonies, with each male guarding a small territory of 5-7 shells and their resident females.

Don't worry about aquascaping the aquarium before adding your shell dwellers, as they will move the shells and the substrate as soon as they move in. Just toss the shells in and spread them across the bottom. The fish will move and bury the shells very quickly.

N. multis over shell bed
N. multis over shell bed

Water Parameters for Tanganyikan Shell Dwellers

In order to keep the water appropriately hard and alkaline I like to use the Seachem line of Cichlid Lake Salts and Tanganyika Buffer. These products should only be added to new water during water changes, as they do not evaporate out over time. You will need to do some testing to determine the hardness and alkalinity of your water in order to dose correctly.

Although N. multifasciatus come from a lake with a 9.0 PH, don't put too much effort into chasing that PH value. Unless you find wild caught specimens, most fish will be able to adapt to a PH closer to 8.0. Stability and consistency are more important than precision. Always be careful when adjusting PH and test the water before and after you add buffering products to prevent large swings.

Temperature for Tanganyikan Shell Dwellers

Temperature should be at the lower end of the lake's range (below 80 degrees F), as N. multifasciatus actually live at depths of 50-100 feet below the surface. I keep mine at 77 degrees F and they do very well at that temperature. Anything between 75 - 80 degrees fahrenheit should be acceptable.

Filtration for Shell Dwellers

I run an Aquaclear hang on back filter on my Multi tank. I recommend using an intake sponge to prevent fry from being sucked into the filer. A canister filter or sponge filter would both be viable options as well. Any form of filtration will work, as long as you are performing regular water changes. Your preferred maintenance routine should determine the filter you use.

Breeding Neolamprologus Multifasciatus

N. multifasciatus over shell bed
N. multifasciatus over shell bed

Shell dwellers are one of the easier fish to breed as long as you are providing them with clean water and the right conditions. Males will compete for control of a harem of several females. Breeding takes place in the shells and the fry will be born inside of a shell. Feeding a good variety of quality frozen and live foods will usually stimulate breeding. I like to offer live or frozen baby brine shrimp, microworms, krill flake, and spirulina flake. Live daphnia, frozen cyclops, or any similar food will also work.

The first sign of breeding activity is usually a group of small fry poking their heads out of a shell. The fry will be able to eat microworms, crushed flake, and live baby brine as soon as they are big enough to leave the shell. They will remain within a couple inches of their home shell for the first few weeks of their life.

Eventually you will end up with more fish than shells, which is the limiting factor on the size of the colony. At this point some fish should be removed and rehomed to avoid over crowding. Fortunately Multies are typically an easy fish to get rid of due to their small size and amazing behavior.

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About Melanotaenia Praecox

Known commonly as the Neon Dwarf or Praecox Rainbowfish, Melanotaenia Praecox are a small, colorful rainbow fish from New Guinea. They are an interesting schooling species that is best kept in larger groups of 8-10+, with at least a 1:1 ratio of females to males. An excellent community fish, they do well in peaceful setups that are heavily planted.

I keep 20 dwarf neon rainbows - 10 males and 10 females - in my 90 gallon rainbowfish community tank. The neons share this aquarium with other larger rainbowfish species and they get along with everyone. Praecox are active swimmers and will go after most foods pretty aggressively once they're settled into the aquarium, which makes them fun to watch.

Sex can be easily determined based on size, body shape, and fin color when the fish reach adulthood. Both males and females will have shiny, iridescent blueish bodies. Adult male Praecox have red fins, while females have orange/yellow colored fins. Males will also have a larger, taller body shape with a more pointed head while healthy adult females will be smaller than the males.

Male and Female Dwarf Neon Rainbowfish
Male and Female Dwarf Neon Rainbowfish

Setting up a Breeding Tank

Breeding Aquarium
Breeding Aquarium

A breeding aquarium for Melanotaenia Praecox should be kept 73-82°F (23-28°C), and at a PH slightly above 7.0.  As in most cases, aiming for stable parameters is better than aiming for perfection. A tank with a sponge filter is ideal for this because the fry of this species are incredibly tiny at birth.

Dwarf neons are egg scatterrers, so the ideal setup is a bare bottom aquarium with a large portion of java moss or a spawning mop.  I have used both as egg laying substrates and the fish readily spawned in both the moss and the mop.

The purpose of the spawning mop is to give the eggs a safe place to stick to that can be removed and transferred to a rearing tank if desired. You can make your own spawning mop using wool string, or buy them pretty inexpensively.

Selecting and Preparing Breeding Stock

Before moving fish into a breeding tank you'll want to make sure you have a few healthy, well fed adult specimens ready to breed.  As with any fish, a high quality diet consisting of a good variety of live, frozen, and dried foods is ideal to get them ready to breed.  Females need to eat well to produce lots of eggs, and males will display their best colors and breeding activity when well fed.

Look for males with a nice tall body and colorful fins.  Females should be grown out and well fed before being selected for breeding.  I have had good success just selecting one pair and placing them in a breeding aquarium together. 

The pair may take a couple of days to settle into the tank before they start to show breeding behavior.  The male will display for the female and the two will swim through their chosen spawning site, which should be a spawning mop or moss portion.  Eggs will be deposited over the course of a few days, so dont pull the pair out as soon as you see eggs.

Praecox Eggs
Praecox Eggs

Praecox eggs are very small so they can be challenging to spot. Once the pair has spawned, they can be removed from the breeding tank and the eggs will hatch within a week. You can also carefully move the spawning mop or moss with the eggs on it into a fry growout tank with a sponge filter.

Caring for M. Praecox Fry

When dwarf neons hatch they are tiny.  Like, crazy small - less than half a centimeter.  Because they are so small these fry need very fine powdered fry foods, cultured infusoria, or live microworms to feed on.  I would recommend having a combination of very small foods ready before your fry hatch.  Even newly hatched baby brine shrimp will be too large for newborn M. praecox to swallow.

After a week or two on starter fry foods the young should be large enough to take baby brine shrimp, which you should know how to hatch yourself if you want to breed fish.  Baby fish should be fed multiple times a day for optimal survival.  They have very short digestive systems and no accumulated body mass to live on, so they need to eat frequently.

Young M. praecox

M. praecox fry should eat readily and will put on some decent size in just a few months if well fed.  These fish are amazing to watch in large schools, so successful breeding is very rewarding.

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Outdoor Guppy Tub
Outdoor Guppy Tub

Outdoor Fish "Tubbing"

Keeping fish in small, temporary outdoor ponds or tubs is often referred to as "tubbing" among fishkeepers. The most popular fish to keep in tubs are probably live-bearers. This includes guppies, Endlers, mollies, platys, and many other species. These tubs are unfiltered and in many cases go an entire season without a water change. This summer I'm keeping guppies in a 100 gallon container in my back yard.

What Temperatures Can Guppies Survive Outside?

Unlike goldfish and koi, guppies can't survive outdoors in cold weather. While most sources will list the minimum acceptable temperature for guppies anywhere from 65°F - 72°F, they can tolerate water as cold as 60°F for short periods of time.

Where I live in Colorado, there is only about a 3 month window every year when temperatures are consistently warm enough for a guppy tub. The chart below shows daily average high and low temperatures specific to my area.

Colorado Average Monthly Temp
Colorado Average Monthly Temp

Water doesn't heat or cool as quickly as the surrounding air. This means the water in an outdoor tub usually won't reach the daily high or low temperature on a given day, it will drift gradually between them. The average water temperature should be near the center of the daily range. There will also be a temperature gradient between the water's surface and the bottom of the tub, assuming it is sufficiently large.

Actual Guppy Tub Temperature Observations

During the month of June I took temperature readings of my guppy tub at least once every day, up to 3 observations per day, for a total of 55 observations. The data I collected is shown in the chart below. You can see that on very hot days the water temperature (measured using a floating thermometer at the surface) reached as high as 86 degrees. This only lasted a few hours until the sun set, but I am planning on setting up some afternoon shade for the tub going into the hottest part of the year. As you might expect from historical weather data, the average water temp observed in June was 71.5°F.

Note: All of these temperature observations were made at various times throughout the day between 7:00 AM and 7:30 PM.  The highest temperatures were observed in the late afternoon after several hours of direct sun.

Water Temperature of the Guppy Tub Throughout June 2019
Water Temperature of the Guppy Tub Throughout June 2019

High 86
Low 58
Average 71.5

I kept the guppies in an unheated aquarium indoors at 68°F - 70°F for several months in preparation for this project, during which time they continued to breed and grow. I did not observe any deaths during the month shown here, and saw new fry after about 3 weeks of the guppies being in the tub. Based on my observations, guppies are able to tolerate relatively large daily swings in temperature, as long as the extremes are not too hot (above 90ºF) or too cold (below 60ºF).

Outdoor Guppy Tub Container

I chose a 100 gallon Rubbermaid stock tank for this guppy tub project.

100 Gallon Rubbermaid Stock Tank
100 Gallon Rubbermaid Stock Tank

I've seen others use rain barrels, kiddie pools, pond liners, etc. I wouldn't use anything that holds less than 40-50 gallons, because water parameters are going to be more stable in a larger volume of water. You should also avoid any container that is too tall and skinny, as this will make viewing and catching the fish difficult. Stock tanks (horse troughs) are the ideal shape for a garden pond.

Guppy Tub on Day 1
Guppy Tub on Day 1

Outdoor Guppy Tub Plants

Floating Plants
Floating Plants

Plants are an essential requirement for outdoor fish tubbing. Since you won't be performing many water changes, plants will help to remove excess nitrogen. They also compete with algae for nutrients. A pond without any plants will quickly turn green after a few days of sunlight. Any aquatic or marginal plant could be used in an outdoor guppy tub project. Some common pond plants include water lilies and water lettuce.

Shop Pond Plants on Amazon

I set up this pond with some duckweed & water lettuce from my Endler breeding aquarium.  I also added a large portion of najas/guppy grass. Guppy grass can be grown either rooted or as a floater, and is often used in breeding live-bearers. Floating plants are a good choice for an outdoor tub because the roots provide shade and cover for the fish, and they don't require any substrate.

Adding Fish to an Outdoor Tub

Ideally you'd want to have an outdoor tub filled and planted for several days before introducing fish. This gives the water an opportunity to age in the sun, as algae grows and infusoria begin to develop. I added water from established aquariums to my 100 gallon stock tank, and let it sit for 3 days before adding any fish. As mentioned above, I also prepared my guppies by keeping them in an unheated aquarium all spring before they moved into the tub.

Guppies
Guppies

Maintaining Water Quality in an Outdoor Tub

Water Changes

In a perfect world, all water that evaporated out of a tub would be replaced by rainwater, and all wastes would be absorbed by the plants. Of course that's not the world we live in. You should check the nitrates in an outdoor tub just like you would with an aquarium, and do a water change if they rise over 20 ppm. I've found that a 30% water change every 2 weeks is adequate in my pond. This probably wouldn't be necessary if I had enough plants to entirely cover the surface.

Aeration

I use a solar powered air pump to oxygenate the water. More on that in this post, but you can get the solar panel I'm using here on Amazon. You'll also need an air pump that can run off USB power, which I got from Aquarium Coop (https://www.aquariumcoop.com/). You can also buy them on Amazon. This pump runs about 10-11 hours per day (you know, solar) and does a good job keeping the water from getting stagnant.