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The Reef Damsel’s Distress Call

Researchers at James Cook University in the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) have uncovered an interesting feature of the Damsel reef fish family. We watch our fish dart in and out of crevices when they get scared in our aquariums but little did we know they are, at the same time, releasing a chemical signal from their skin and scales to ward of predators, and give themselves a fighting chance for survival. This is a finding not new to the science of fish, but the surprise conclusion was the benefit to the fish releasing the chemical: “When damselfish release their chemical alarm on a coral reef, lots of additional predators are attracted to the cue release area,” says Professor Mark McCormick from the Coral CoE. 151027213415_1_900x600The added presence of predators would seem counterintuitive to anyone reading this, but what researchers would like us to recognize is the increased presence of predators can cause confusion at the predation site, allowing the fish that released the chemical signal additional distraction for escape. “When caught by a predator, small damselfish have almost no chance of escaping their fate as the predator’s next meal. However, when another fish predator is attracted to the capture site, prey will escape about 40 percent of the time,” added Professor McCormick. “For decades scientists have debated the evolutionary origin of chemical alarm cues in fish,” says study lead author, Dr. Oona Lönnstedt, now a research fellow at the University of Uppsala. The percent increase of escape establishes additional evolutionary benefit to the defense mechanism of Damsel fish, while opening a new avenue for understanding the behaviors of reef fish. Read the entire article here!… More:

Dealing With Red Bugs and AEFW

When I first started keeping reef tanks a long time ago there seemed to be much less awareness of certain pests that can infiltrate and harm a reef tank. “Back in the day” wild colonies were all the rage and reef keepers were not as diligent about checking for pests. Dealing with Red Bugs and AEFW (Acro Eating Flatworms) wasn’t even on my radar when I had my first 90 gallon reef and it took a while before it crept into my conscience when I had my 120 gallon reef. The 120 gallon reef was my best tank to date and it was dominated with large and colorful SPS that grew from small frags and colonies My 120 Gallon Reef Tank However, over time, a few acros didn’t look as colorful as others so I tried certain remedies like changing my lighting setup or doing more water changes but nothing seemed to help.

Long Island Collecting Log: Cold-water strays

 Typically, my last dive of the season in New York takes place by late October, but, since poor weather kept me out of the water for the last two weeks of the month, I thought I would push the limits of my cold tolerance with a November dive this year.  With water temperature down to 59°F, I knew I wouldn’t last long in the 7mm wetsuit I use all summer, and I didn’t expect to see any tropical fish, but after a break in the rough autumn weather and with visibility improving, I just couldn’t resist.… More:

Reef Threads Podcast #250

Should we take marine animals from the reefs for our viewing pleasure?

In our 250th podcast, a discussion about marine-fish captive breeding and Orca breeding leads to an exchange about keeping wild animals captive, the current state of our hobby, and how collecting and keeping marine animals fits in the larger animal-treatment arena. Basically, we address some difficult questions. After you’ve listened, share your thoughts here or on the Reef Threads Facebook page.

Download the podcast here, or subscribe to our podcasts at iTunes. Also, follow us on Twitter @reefthreads.—Gary and Christine

Sponsor: Rod’s Food
Rod’s Food website

Breeding yellow tangs
Rising Tide Conservation Captive Bred Yellow Tangs

Breeding Orcas
Sea World To Challenge California Ban On Orca Breeding, Francis Yupangco,

UPDATE: Yellow Tang Progress at Oceanic Institute!

Oceanic Institute of Hawaii Pacific University is making some great headway with rearing Yellow Tangs! Check out the videos of the 36dph and 49dph groups at the Rising Tide Facebook Page:  "The [Yellow Tang] group that is 70dph only has a handful remaining, and just a couple of that handful look like the photo. We are observing a pretty significant gap in development within cohorts, where some fish are extremely stunted compared to their siblings. However, we are really excited to be seeing the dorsal and anal fins forming, which is signaling that the transition to settlement is close! The next group that we have is 49 dph today and many of these fish appear similar in development to our day 70 group. This tank has more than 100 remaining, and they appear really strong, much more lively and active than the day 70 group did at the same age.

Freshwater Dips and Seahorses

Occasionally a seahorse hobbyist runs into a situation where a freshwater (FW) dip is indicated. A FW Dip can be used as both a therapeutic and a diagnostic tool. As a therapeutic tool it can help rid the seahorse of ectoparasites on the body, in the oral cavity, as well as in the gills. As a diagnostic tool, observation during the dip will give you a good idea if there is a parasitic load or not. It can also be done prophylactically on new arrivals from suspect sources, on wild caught (WC) specimens or when a tank mate has had known parasitic load. We have been doing FW Dips for over 11 years. We have found that every species we have encountered has handled FW Dips just fine

Not Dwarf Seahorses, Baby Seahorses

Left, Tiger Tail seahorse from MaryG, right Dwarf Seahorse, photo by Felicia McCaulley Regular readers of are aware of my concern over juvenile seahorses being sold far too small and young. It came to my attention recently that sometimes very young juveniles of larger seahorse species are being sold as Dwarf Seahorses Hippocampus zosterae due to the exceptionally small size they are being sold at. This issue came to light by way of the our forum member Maryg. She asked to confirm the species of a couple seahorses sold through her local fish store as dwarf seahorses. The seahorses in question were in fact juvenile Tiger Tail Seahorses Hippocampus comes

Chromis Make Gender Adjustments to Combat Global Warming

A new study from the University of Sydney Australia has found that the Spiny Chromis reef fish can manipulate the gender of their offspring to combat the gender bias created by increasing ocean temperatures. “The research findings are significant because global warming poses a threat to species with temperature-dependent sex determination (TSD), such as reptiles and fish, potentially skewing the sex-ratio of offspring and, consequently, breeding individuals in a population,”said lead author and UTS Chancellor’s Postdoctoral Research Fellow Dr Jennifer Donelson. “A reduction in the proportion of females in the population could be especially damaging because population growth rate is often constrained by female fertility.” A-poly-rubble-copy_0The understanding of how prenatal gender adjustments can be made is a bit of a mystery to scientists but the findings certainly add to the hope that ecosystems will adapt to the changes occurring all over the globe. “Just precisely how our study species, the Spiny Chromis coral reef fish, engineer these amazing adjustments is unknown and is something we are now investigating. What we do know however is that oceans are warming and emerging research is showing the importance of transgenerational plasticity in reducing the negative impacts of climate change on species with TSD.” Read more here!… More: is the world's leading destination for sustainable coral reef farming and the aquarium hobby. We offer a free open forum and reef related news and data to better educate aquarists and further our goals of sustainable reef management.