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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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This DIY LED Bucket Light was inspired by a similar build by The King of DIY on Youtube. It only cost about $15 to make, and the entire project took less than an hour.

This light hangs above my 40 gallon Lake Tanganyika shell-dweller aquarium. It uses a single LED bulb, which puts out plenty of light for a shallow 40 breeder layout with no plants.

LED Bucket Light
LED Bucket Light

Materials

All materials needed for this build are listed below, with links to buy them on Amazon.

  1.  1 x two gallon bucket (any color or style)- link
  2.  1 x clamp light (with 5.5 inch reflector) - link
  3.  1 x LED bulb - link
  4.  2 x eye bolts - link
  5.  1 x chain - link
  6.  1 x shelf bracket - link

I had all of the hanging hardware and the LED bulb laying around already. Most of these materials can be swapped out for something similar. For example, you could replace the bucket with a plastic pot.

How to Build a DIY Bucket Light

clamp light

1. Take apart the clamp light:

First remove the clamp. They are usually held on to the base by a thumb screw and come apart easily. Unscrew the metal reflector from the light as well, so that you have just the light socket base and the power cord.

2. Drill a hole in the bottom of the bucket

just large enough for the light socket to pass through, but not as large as the black plastic base. Insert the light socket into the hole as show below. Screw eye bolts into the base of the bucket.

Bucket Base

3. Assemble the light:

Insert the metal reflector into the bucket and screw it onto the plastic base. Install an LED bulb appropriate for the wattage and size of the light socket. The light is now complete.

Inside of Bucket Light
Inside of Bucket Light

4. Hang the light.

This step is pretty straight forward. Attach the chain to the eye bolts and hang it from your ceiling or wall.

DIY Bucket Light in use
DIY Bucket Light in use

Amazon Prime Day 2019

Amazon Prime Day is Amazon's annual "holiday" that’s exclusive to Prime subscribers. Historically, Prime Day has launched in mid-July, and Prime Day 2019 is actually two days long - July 15th and 16th. Deals begin at 12 AM PT on July 15th! If you don’t have Amazon Prime, you can sign up for a free trial just to take advantage of the deals. You may not find absolutely everything on your wish list during the Prime Day discounts, but it’s the best opportunity to stock up on gifts during the summer.

Best Amazon Prime Day Deals for Aquarium Enthusiasts

The best aquarium and fish related deals will be listed here and this post will be updated during the sale as new deals go live.

See the full list of Aquarium related Prime Day deals here

Smart Plugs - Control your Aquarium Equipment Remotely

Shop Smart plug deals on Amazon

Smart plugs that are wifi controlled are a good way to control your lights, circulation pumps, or any gear you want to be able to switch on and off easily.

Kasa Smart WiFi Plug by TP-Link – Smart Plug, No Hub Required, Works with Alexa and Google (HS100)

Kasa Smart WiFi Plug by TP-Link: $11.68 on sale

Amazon Smart Plug, works with Alexa

Aquarium Lighting Deals

NICREW ClassicLED Plus LED Aquarium Light, Full Spectrum Fish Tank Light for Freshwater

Nicrew Aquarium Lights are on sale on Amazon for Prime Day!

I wrote this review on the Nicrew LED lights - these are an awesome deal on sale. Now is a good time to upgrade your old florescent lighting and get some LEDs on your setup.

NICREW Submersible LED Aquarium Light, Hidden White with Blue LED Light Stick for Fish Tank

NICREW Submersible LED Aquarium Light: $10.39 on sale

Aquarium Air Pumps - Always have a Backup!

Its critical to have a backup air pump in case your existing pump fails. Even better is to have one of these small USB air pumps that can be powered by a portable power bank.

I use one of these little gadgets on my outdoor guppy pond, and they produce a lot more air flow than you might expect.

Mylivell Quietest Aquarium Air Pump Ultra Silent High Energy Saving Oxygen Air Pump Aquarium for Fish Tank with Air Stone and Silicone Tube

USB Air Pump: $10.39 on sale

See all "Aquarium" Prime Day Deals 

This Link will take you to the full list of Aquarium Prime Day Deals