Green Slimer Coral Care: Growth, Placement, Lighting, & Water Flow

Do you want to try growing some epic acropora (acro) corals, but you don’t know where to start… Stop what you are doing, and check out the Bali Green Slimer coral!

The Bali Green Slimer coral (Acropora yongei) is a unique-looking staghorn acropora coral and an all-time favorite with reef hobbyists for more than 20 years. While it may not have a range of fancy colors or psychedelic tentacles like the Walt Disney acro, the slimer’s neon green color makes it stand out from the crowd, dominating your SPS (small polyp stony) reef tank. 

When the Green Slimer first entered the trade, aquarium hobbyists saw robust and rapid growth from the get-go, and with that, word spread fast that these acros are a must for any SPS enthusiast. Soon, the distinctive Green Slimer was popping up in every reef tank around the world.

So, let’s dive in and see what makes the Green Slimer so epic!

Green Slimer Care

With tough genetics and tolerance to fragging and transportation, the Bali Green Slimer makes it perfect for novice aquarists that want to take on the ‘acropora challenge’. If you have successfully kept less demanding SPS corals like montipora, then give the Green Slimer a go!

Green Slimer Summary

  • Scientific/Latin Name: Acropora yongei
  • Family: Acroporidae
  • Common Names: Green Slimer, Bali Green Slimer
  • Care Level: Easy (in an SPS tank)
  • Temperament: Peaceful
  • Lighting: Moderate to high (PAR 300-450)
  • Water Flow: Moderate to high
  • Placement: Bottom, middle or the top region
  • Growth: Fast

Green Slimer Water Conditions

  • Temperature: 75° – 80 °F
  • pH: 8.1 – 8.4
  • Salinity: 1.024 – 1.026 (1.025 is ideal)
  • Alkalinity: 8 – 9.5 dKH
  • Nitrates: <10 ppm
  • Phosphates: <0.10 ppm
  • Calcium: 420 – 440 ppm
  • Magnesium: 1260 – 1350

It is important to maintain proper alkalinity, calcium, and magnesium levels, as they all help to build the Green Slimer’s calcium carbonate skeleton. To prevent large fluctuations, it is highly recommended to buy a dosing pump.

Green Slimer Growth

Once your Green Slimer has fully established in your reef tank, you can expect it to grow fast. These acros are known to grow like crazy, so you should give them lots of room to reach their full potential inside your aquarium.

For example, a good friend of mine bought a Green Slimer and placed it in his 225-gallon reef tank. Within the first year, it nearly took over the whole corner of his aquarium, touching and creeping up on other corals, and even extending beyond the water. 

This is where fragging comes in; fragmentation will be your best friend when keeping rapid growers like the Bali Green Slimer.

Fragging Green Slimer Corals

Just like most SPS corals, the Green Slimer is a simple coral to frag. 

Take a pair of coral cutters (bone cutters) to cut off the branch or branches of choice. If you wish to keep your coral frag, it can easily be glued onto a frag plug, but, just be prepared for its namesake slime! 

The name is a big giveaway to its slime/mucus production. As mentioned, Green Slimers can tolerate fragmentation, however, as soon as you start fragging pieces off, your coral will quickly produce a slimy mucus when disturbed. So, if you are selling on your frags, wait a few days to let your Green Slimer calm down before sending it in the post!

Green Slimer Placement

Most of the time, the origin of corals gives you a rough idea of where a coral should be placed inside your aquarium, and if the name hasn’t already given it away, Bali Green Slimers come from the Indo-Pacific region. For those that have been lucky enough to visit the Indo-Pacific region to go scuba diving, you would have seen that most acropora corals are found on sloping reefs between 16 and 82 feet. This depth and location is to shelter the corals from wave action. 

Saying that, the Green Slimer is not fussy when it comes to placement in captivity, as long as you provide it with the correct lighting and water flow requirements. 

With any coral, it is best to place it lower down your aquascape, gradually moving it up to its final destination. Why? Well, because your Green Slimer needs time to acclimate to its new conditions, as every reef tank setup will be slightly different.

As for the Slimer’s rapid growth, we recommend placing your acro halfway to give it space to grow and branch out. To secure it to your aquascape use reef-safe IC gel glue or putty. In my experience, an exposed rock or ledge is best for the Green Slimer to receive direct flow and lighting.

Green Slimer Lighting

Following the trend of other acros, the Green Slimer thrives with moderate to strong lighting, and the majority of aquarist’s would agree that high lighting serves this particular acro very well. 

However, this does not mean you should turn up the lighting intensity to maximum capacity and blast your Green Slimer… Lighting that is too intense can result in bleached acropora, turning it white

For best growth and coloration, you want to aim for a PAR level between 300 and 450, and a 14-20K color spectrum. As Bali Green Slimers are not fussy with the type of lighting fixture you have, LEDs, T5 fluorescents, or metal halides can all grow your Slimer as long as the proper PAR level is provided. 

But, one thing I have found with the Bali Green Slimer coral is the time of acclimation with lighting. Under metal halides, they seem to take a little longer to acclimate than LEDs or T5s.

Green Slimer Water Flow 

Water flow is an important factor in keeping corals. As corals cannot move around, they rely on sufficient water flow to capture food, distribute their offspring, help remove metabolic waste, and keep uneaten food and other detritus from settling on their polyps, which can make them sick. 

When it comes to acros and other SPS corals, they require a strong water flow with nonlinear flow. Thanks to the technology we have now, most modern wave action powerheads can provide these requirements for your Green Slimer coral. 

Green Slimer Feeding 

Acropora corals like your Green Slimer rely on the symbiotic algae (zooxanthellae), that live inside its tissues for most of its nutritional requirements, but they also benefit from direct feeding. 

There are many coral food options available that make perfect treats for acros! I recommend feeding your Green Slimer with a mixture of meaty rotifer-based foods that contain vitamin additives and highly unsaturated fatty acids (HUFA). Coral foods such as Oyster-Feast and/or Roti-Feast are great. 

Whichever food you feed your Green Slimer, it is essential that the size is small enough for your coral’s polyp to fully ingest it. To directly feed your Green Slimer, target feeding with a turkey baster is recommended. Target feeding not only ensures your Green Slimer has eaten but also helps keep nitrates and phosphates down inside your aquarium.

Final Thoughts

There is no doubt that the Bali Green Slimer is a type of staghorn coral to get your attention. The Slimer’s vibrant neon green coloration and ease of care make it a perfect candidate for reef hobbyists wanting to up their game and dive into acropora corals. 

So ‘water’ you waiting for, go check out your local fish store or search the internet to see where the nearest Green Slimer is to you!

  • Roy Lee

    I have an unhealthy obsession with reef keeping and maintaining successful tanks. If you haven't noticed from the website, I love everything related to saltwater tanks like coral, fish, and everything else in between. Lee Roy

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