Hi all
I would like to ask you for some advise on the probable cause of fish deaths in my marine tank (apologies for being a little long winded)
I bought the established fish tank with fish (2 clown and one coral beauty) a few months ago. Before I purchased any further fish, I ensured environmental conditions were settled and non of existing fish were exhibiting any signs of disease/parasites by waiting for a period of approx 6 weeks.
After 6 weeks passed we purchased 2 bannerfish from an aquarium, which settled in really well/fed well and had no behavioural problems.
Approx one week the aquarium received and new stock of fish including Royal gramma and 3 days later we were allowed to purchase it. The fish settled in and although hiding, fed straight away. However after approx 4 days of having the it stopped feeding. I saw it a day or 2 later upside down and contacted the aquarium as was concerned. They advised this is usual behaviour and not to worry. The following day (Xmas eve) it was dead. This followed with the 2 bannerfish dying hours apart on Xmas day with loss of colour, rapid breathing, twitching. When I contacted the aquarium after boxing day they told me to bring water sample for testing, howver these were all well within acceptable parameters as I'm an ex water quality scientist and well maintain my aquarium. I advised it sounded like a parasite had introduced by the new fish esp as it was the royal grammar died first within days of entering the tank. The aquarium dismissed this suggestion and advised it was an ammonia spike or external contaminant. Again due to my background I believed this was not the case.
Then a few days later, one of the clownfish which has been in there from the beginning without symptoms began with the same as the bannerfish and died that day. I rang the aquarium and they again tried to say was ammonia spike but to send them pictures. At this point they confirmed as velvet and suggested i try treatment treatment. After approx 3 days of treatment, my other clown showed symptoms and died that days. I continued treatment for a further 3 days but finally my coral beauty also died of the same. I obviously believe that the most likely scenario would be the royal gramma brought the velvet into the tank.
The aquarium has advised that due to the gramma dying and not being noticed straight away will have started an ammonia spike. This will have caused the other fish especially the wimple’s to become stressed, the fish loosing colour and struggling to breath are the main symptoms of an ammonia spike.
They went onto advise that in relation to the velvet that broke out after the fish death. This can be a common occurrence in marine tanks due to the nature of velvet. Most established marine tanks will have the organism that causes velvet (oodinium) in the tank, it’s a free swimming organism that very easily turns parasitic. As with almost all parasitic infections, most fish can fight off minor infections providing their immune system is strong however can infect any fish at any time.
We agree as a team that the cost of the royal gramma should be reimbursed to yourselves as it didn’t settle, and although the circumstances of the wimple fish was out of our control and as a gesture of good will also reimburse you for the two wimple fish also.
As a result of the above I find out extremely hard to believe that there was a fish death caused by an ammonia spike, followed immediately by an outbreak of velvet which killed the remaining fish in the tank. The aquarium has also failed to provide explanation as to why the royal gramma died.
Therefore I would really appreciate some external expert advice of the situation above
Welcome to Reef2Reef!
It does sound like it could have been Amyloodinium/Velvet. Some additional points will solidify that though:
Did any fish survive the whole process? If so, what species?
Are the invertebrates in the tank doing well? If so, you can almost 100% rule out water quality issues - those will harm shrimp, snails and corals long before harming the fish.
They told you: "Most established marine tanks will have the organism that causes velvet (oodinium) in the tank,..." That is untrue. The virulent life cycle of Amyloodinium means that if is is present, it goes into an acute infection.
Here is an excerpt I wrote up about this disease:
Amyloodinium (a.k.a. marine velvet disease)
Cause
Commonly known as “marine velvet” in hobby parlance, Amyloodinium is caused by a dinoflagellate protozoan that can create severe epidemics in aquariums. Furthermore, it can infect fishes that are normally more resistant to other marine protozoan diseases (e.g., Cryptocaryon), such as sharks, rays, and eels.
Symptoms
The life cycle of Amyloodinium is very similar to that of Cryptocaryon, as are the possible treatments available, but it has less distinctive early symptoms and can cause fish mortalities much sooner than other protozoan infections—sometimes within 24 hours of the onset of obvious symptoms. This disease begins as an infection of the fish’s gills, and only in advanced cases does it spread to the skin, giving it a “velvety” look. Symptoms include rapid breathing (greater than 140 beats per minute) and hovering in the current from pumps.
Beginning aquarists often miss the first symptoms and commonly report, “All my fish suddenly died, but the invertebrates are all fine.” Since invertebrates are typically more sensitive to water-quality issues than fish are, the fact that the fish suddenly died but the invertebrates were unharmed means that water-quality problems can be ruled out. That leaves a fish disease, and Amyloodinium can often be diagnosed without even needing to perform a necropsy on the fish due to the rapidity of the fish loss!
Diagnosis
The key to early diagnosis of Amyloodinium is to monitor the fish’s gill health by taking regular fish respiration rates. This is a simple matter of counting the number of gill beats in one minute for a representative fish in the aquarium and then rechecking the respiration rate every few days to watch for any elevation in that rate.
Newly acquired fish that are not being treated prophylactically should have their respiration rate checked daily, as these fish are the ones at greatest risk of developing this disease. The actual respiration rate is not that important, it is a rise in the rate that must be monitored for.
Different species of fish will respire at different rates. Smaller fish breathe faster than large ones, and fish in warmer water will respire faster as well. Typically, tropical fish will respire between 60 and 120 gill beats per minute. If you can’t view the fish for a full minute, you can try counting for 15 seconds and multiplying the result by four.
Knowing your fish’s normal baseline respiration rate is vital; any rise in that rate above 30% (and not attributable to something else, such as the fish being chased by a tankmate) should be viewed as a possible symptom of this disease.
Treatment
Treatments for Amyloodinium cannot be performed with invertebrates present, yet the entire tank usually needs to be treated in order to eradicate it. Copper sulfate at 0.20 ppm for 14 days is one often-used cure. Chloroquine at 8 to 15 ppm as a 30-day static bath is another treatment that has been used with good success. Amine-based copper medications for 30 days is also effective.
Performing a five-minute freshwater dip can buy some time in order to develop a full treatment. Hydrogen peroxide dips at 75 to 100 ppm and moving the fish to a sterile aquarium has been used in aquaculture. Lowering the tank’s temperature is rarely effective. Likewise, hyposalinity treatments (sometimes recommended for Cryptocaryon treatments) will not work for Amyloodinium.
Jay
