Benefits of being a member of the World Aquatic Veterinary Medical Association.

Posted on by TheFishVet - Richmond's School of Fish

Membership allows you to access a wide range of resources including contact with leading aquatic veterinarians through the listserve, providing expert opinion on a case, diagnostic imagery and peer review, Publications such as the quarterly Aquatic Vet News keep you up to date with professional developments and issues within aquatic veterinary medicine. The image library can help in research or to jazz up those PowerPoint presentations! Whilst the aquatic vet WebCEPD provides live webinars, themed courses and presentations suitable for training staff, relicensure or personal professional development.

Check out WAVMA’s website: http://www.wavma.org/

Bacteria and ornamental fish

Posted on by TheFishVet - Richmond's School of Fish

The warmer Summer weather means that it is the peak time of the year when bacterial infections and other diseases break out if the environmental conditions are suboptimal.

When disease hits, you will need to act quickly and upon the advice of your fish veterinarian.

This article is timely.

Bacteria and ornamental fishnext term

Gregory A. Lewbart MS, VMD, Dipl.ACZM Corresponding Author Contact Information, a

a Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, Raleigh, NC, USA

Available online 31 May 2006.

Bacterial disease is the most common infectious problem of ornamental previous termfishesnext term, and most bacterial infections are caused by gram-negative organisms. The majority ofbacterial previous termfishnext term pathogens are natural inhabitants of the aquatic environment, whether it be freshwater or marine. Extrinsic stressors, including shipping, crowding, poor water quality, and inadequate nutrition, may predispose an ornamental previous termfishnext term to bacterial disease. This article reviews the important bacterial pathogens of ornamental previous termfishnext term in a systematic manner, discusses the problems of over-the-counter antimicrobial compounds and antibiotic resistance, and reviews treatment and management options.

Airline pilot startled by flying shark! NZ.

Posted on by TheFishVet - Richmond's School of Fish

I have to say that my shark hasn’t strayed and is still in my house… at least it was the last time I checked…

http://www.watoday.com.au/travel/travel-news/airline-pilot-startled-by-flying-shark-20120104-1pk9o.html

How tough is the abalone herpesvirus?

Posted on by TheFishVet - Richmond's School of Fish

The Victorian and Tasmanian abalone industries took a big hit recently from a viral disease. Efforts are now in place to curb a recurrence. This paper adds knowledge to the biosecurity measures that all abalone farmers, commercial abalone divers and recreational abalone fishers should put in practice, especially when moving between sites and with the recreational abalone fishing season well under way.

Aquaculture
Volume 329, Number 2 (January 2012)
Abalone herpes virus stability in sea water and susceptibility to chemical disinfectants
Authors: Serge Corbeil, Lynette M. Williams, Jemma Bergfeld, Mark St.J. Crane
Author Affiliations:
no affiliations available
Source: Aquaculture, Volume 329, Number 2 (January 2012)
Page Numbers: 20 – 26
Available Full Text:
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Format: PDF
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Abstract: Experimental infection models using immersion and injection challenges were developed to investigate the effects of various physicochemical treatments on the abalone herpes virus (AbHV), an emerging virus causing viral ganglioneuritis in abalone in Australia. To determine stability at different temperatures, the virus was held at 4, 15, or 25°C for 1, 5, and 12days prior to immersion challenge of naïve abalone. Mortality curves indicated that when held for 1day in sea water at 4°C and 15°C the virus remained infectious and highly pathogenic. In addition, the virus retained partial infectivity after 5days held at 4°C. Histological examination of abalone tissues following viral exposure confirmed the presence of lesions typical of abalone viral ganglioneuritis in animals showing morbidity signs. An additional experiment was performed to determine the virucidal efficacy of three disinfectants (calcium hypochlorite, Buffodineand the non-ionic surfactant Impress). The disinfectants were used at various doses and durations to treat AbHV prior to injection and immersion challenges. Results showed that Buffodineand the non-ionic surfactant Impresswere effective at inactivating the virus with no detectable adverse effects on the abalone’s health. In addition, calcium hypochlorite showed a virucidal effect when used on lower titres of virus prior to immersion challenge.
Citation: Serge Corbeil, Lynette M. Williams, Jemma Bergfeld, Mark St.J. Crane . Abalone herpes virus stability in sea water and susceptibility to chemical disinfectants. Aquaculture, Volume 329, Number 2 (January 2012), pp. 20-26,
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=45A2B7C79E5E35FC54D1

Toxicities of commonly used aquarium remedies.

Posted on by TheFishVet - Richmond's School of Fish

There are many remedies readily available through your local fish shop. But beware that not only can some of these be toxic to your fishes, but also to you. The paper below reveals that toxicity also varies between different types of fishes. Something to consider the next time you reach for a “multi-cure” because removing the disease by killing the host is not usually the best outcome.

Abstract
August 15, 2007, Vol. 231, No. 4, Pages 590-595
doi: 10.2460/javma.231.4.590

Tolerance of benzalkonium chloride, formalin, malachite green, and potassium permanganate in goldfish and zebrafish

Luigi Intorre, DVM; Valentina Meucci, PhD; Domenica Di Bello, PhD; Gianfranca Monni, PhD; Giulio Soldani, MD; Carlo Pretti, PhD
Section of Pharmacology and Toxicology, Department of Veterinary Clinics, University of Pisa, 56124 Pisa, Italy. (Intorre, Meucci, Soldani); Department of Animal Pathology, University of Pisa, 56124 Pisa, Italy. (Di Bello, Monni, Pretti)
Address correspondence to Dr. Intorre.

Objective—To determine tolerance of goldfish and zebrafish to benzalkonium chloride, formalin, malachite green, and potassium permanganate.

Design—Tolerance study.

Animals—Adult goldfish (Carassius auratus) and zebrafish (Danio rerio).

Procedures—Groups of fish (n = 10/group) were exposed to each disinfectant at the therapeutic dosage; at 0.25, 0.5, 3, and 5 times the concentration used for the therapeutic dosage; and at the concentration used for the therapeutic dosage but for 3 or 5 times the recommended exposure time.

Results—In both species, exposure to malachite green at the therapeutic dosage resulted in toxic effects, including death. Exposure to formalin at the therapeutic dosage resulted in toxic effects in goldfish, but not zebrafish, and exposure to potassium permanganate resulted in toxic effects in zebrafish, but not goldfish. On the basis of the ratio of therapeutic dosage to median lethal dosage, in goldfish, formalin was more toxic than benzalkonium chloride, which was more toxic than malachite green, which was more toxic than potassium permanganate. In zebrafish, potassium permanganate was more toxic than formalin and benzalkonium chloride, which were approximately equally toxic and more toxic than mala-chite green. Extending treatment time increased the toxicity of potassium permanganate in zebrafish and the toxicity of formalin and malachite green in goldfish, but did not alter the toxicity of the other disinfectants.

Conclusions and Clinical Relevance—Results indicated that there was no consistency between zebrafish and goldfish in their tolerance to disinfectants, and that therapeutic dosages reported in the literature for these disinfectants were not always safe.

Access article here.

How much nitrate is safe for fish?

Posted on by TheFishVet - Richmond's School of Fish

Contrary to popular belief, nitrate is not good for fishes. Nitrate is the end product of fish wastes and is most frequently removed by performing water changes or by plants. So, it is a good idea to have some aquatic plants in your aquarium and to carry out regular partial water changes and rinsing of your filters.

How much is safe for your fish? This article suggests a nitrate level of <250ppm is needed for turbot.

Aquaculture
  Volume 329, Number 2 (January 2012)
     The chronic effect of nitrate on production performance and health status of juvenile turbot (Psetta maxima)
   Authors: Chris G.J. van Bussel, Jan P. Schroeder, Sven Wuertz, Carsten Schulz
   Author Affiliations:
no affiliations available
   Source: Aquaculture, Volume 329, Number 2 (January 2012)
   Page Numbers: 163 – 167
   Available Full Text:
Full Text: Subscription Required to view full text
Format: PDF
Size: Unknown
Location: Publisher’s Site
Authentication: Publisher’s Site
   Abstract: The chronic effect of nitrate on the production performance and health of marine cultured fish species is still unknown. Thus, the aim of the present research was to evaluate the chronic effect of nitrate on production parameters and health status of turbot (Psetta maxima). Juvenile turbot were exposed to 0mg/L NO3–N (control C), 125mg/L NO3–N (low nitrate LN), 250mg/L NO3–N (medium nitrate MN) and 500mg/L NO3–N (high nitrate HN) for 6weeks in small-scaled recirculating aquaculture systems (RAS). After 42d, biomass yield, length, weight and specific growth rate (SGR) were significantly (p<0.05) lower for LN, MN and HN compared to C. Mortality, food conversion ratio (FCR), condition factor (CF) and splenic index (SI) did not differ significantly (p0.05) between C and LN but were significantly (p<0.05) higher in the MN and HN groups. Hepatosomatic index (HSI), total hemoglobin (Hb) and methemoglobin (MetHb) did not show significant differences (p0.05) between treatments. Thus, nitrate negatively influences the production performance of turbot, even at low concentrations and nitrate management is therefore a key-factor in turbot RAS production.
   Citation: Chris G.J. van Bussel, Jan P. Schroeder, Sven Wuertz, Carsten Schulz . The chronic effect of nitrate on production performance and health status of juvenile turbot (Psetta maxima). Aquaculture, Volume 329, Number 2 (January 2012), pp. 163-167, <http://ejournals.ebsco.com/direct.asp?ArticleID=412791CE5E21268B02DA&gt;
   URL: http://ejournals.ebsco.com/direct.asp?ArticleID=412791CE5E21268B02DA

20 tonnes of dead fish – Norway

Posted on by TheFishVet - Richmond's School of Fish

Forwarded from AquaVetMed

20 tonnes of dead fish wash up on Norway beaches- cause unknown…

January 3, 2012

Troms, Norway – The inhabitants of Troms could hardly believe their eyes on the morning of New Year’s Eve, a very large amount, an estimated 10 to 20 tons of dead herring washed up on the beach, writes Northern Lights. Tromsø city is the ninth largest urban area in Norway by population. The city is warmer than most other places located on the same latitude, due to the warming effect of the Gulf Stream which originates at the tip of Florida.

Various theories abound for the incident but no one knows for sure what’s happened in the popular hiking area in Nordreisa municipality. However, various theories have been tossed around, explains Jan-Petter Jorgensen (44), who stumbled upon the mass death in sight on the beach with his dog Molly. People say that something similar happened in the 80′s, and there is speculation among others on the river which flows into the ocean behind a promontory on the site, may have had something to do with it.

Maybe the fish have been caught in a deprived oxygen environment, and then died of fresh water? Jorgensen estimates each individual fish to be of 100-150 grams, and that the total might be about up to 20 tons. Now he’s worried about what might happen if no one comes and removing carcasses.

See the source (http://tinyurl.com/6q38h7l) for a rather impressive photograph of the incident.

Growing silver perch? Important reading in this blog.

Posted on by TheFishVet - Richmond's School of Fish

I’ve just bought some silver perch for my backyard aquaponics project (I will outline my efforts at designing and construction in future posts). I got them in just before Christmas and all is going well.

One thing I noticed is that their behaviour is very much like sheep. They show a strong schooling behaviour and so where one or two go, the rest will not be far behind.

Like adolescent men at a buffet, these fish are guts when it comes to food! They just keep coming back and back to the surface for food.

I thought I should point backyard and full-time aquaculturists to this invaluable book on diseases of silver perch in case the sh!t hits the fan.

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/209309/Silver-Perch-Diseases-Manual.pdf

Happy fish keeping!

Richmond Loh