The Fish Vet's Blog

I had a question about whether they should purchase a new tank or an old tank. Everyone loves new, but can you go old too?

From a looks perspective, you may notice unsightly water marks as minerals may be deposited on the glass. This can be easily cleaned off using warm water or dilute vinegar. Don’t worry about light scratches on the tank as they will look invisible once the tank is filled.

From a disease point of view, if the old tank is dry and has been out of circulation for several months, then there ought to be no issues. If in doubt, you can always disinfect with chlorine/bleach and then make it fish-safe again by thorough rinsing and by the use of dechlorinators.

From a practical perspective, you cannot be sure whether the tank will hold up or leak, especially if the tank has been dry for some time. Thus, it is always best to fill the tank in stages. Day 1, fill it to 30% capacity. If no leaks, then fill it to 50% capacity on Day 2. On Day 3, it might be safe to fill it to the maximum water level. Leave it for a week at least prior to stocking the tank.

Biologically, when moving fish from their old tank to their new home, make sure you use as much of the old tank gravel, water, furnishings and filtration equipment to avoid bringing about ‘new tank syndrome’. See fact sheet entitled “Ammonia, nitrite and nitrate” at http://thefishvet.com.au/fact_sheets.html

Does the tank size or water volume affect their growth rate? Last year, I attended the Aquavet II course in the USA. I learnt that the most recent research finding for recirculating aquaculture system (RAS) is that the “partitioned aquaculture system” (PAS) may improve yield per unit total volume or area. The PAS works by dividing the pond to allow 2/3 for the biofilter and only 1/3 for the cultured fish to occupy. The reason for the increased efficiency is not yet understood and this could be investigated further in Australian conditions.

So, I did a short semi-scientific experiment of a different kind with four goldfish. Two fish were in Group A, and they spent their time in a 95L aquarium. Two fish were in Group B, and they spent 3 months in a 4500L set up which was compartmentalised to have a similar amount of swimming space as Group A. Pictured below are two goldfish of the same age.

 

The smaller one belongs to Group A. The larger fish belongs to Group B. Look at the difference in size. At the completion of the experiment, body weights of the small fish were 14g and 16g and the body weights of the large fish were 50g and 59g! That’s a whopping 4x heavier!

What implications does this have for fish breeders and farmers? This experiment shows that water volume, rather than swimming space, plays an important role in goldfish growth rates. This may be to do with better water quality? Maybe production of the growth inhibiting hormone was suppressed (link to previous post). Maybe we could get even better results with a flow through system.

 

Check this out!
http://www.news.com.au/travel/australia/whale-injures-surfers-at-bondi-beach/story-e6frfq89-1226675505920

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Yours sincerely,

Dr Richmond Loh DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics & Pathobiology).
Veterinarian | Adjunct Lecturer Murdoch University | President-elect WAVMA |
Secretary Aquatic Animal Health Chapter – ANZCVS.
The Fish Vet, Perth, Western Australia, AUSTRALIA. Mobile Veterinary Medical & Diagnostic Services for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383

Looking for more books? Check out this site.

The NSW Aquaculture Association is holding a 2 day Recirculating Aquaculture and Aquaponic short course you will be interested in.

Tickets are now on sale through the following link:
http://aquacultureaquaponicscourse.eventzilla.net/

Prices are as follows:
General registration will be $280 total for the two days
This is for anyone to register and attend the full two day short course.

NSW Aquaculture Association Members will be $210
This is for full financial members of NSW Aquaculture Association

Students registration will be $230 (a copy of your student ID card will need to be sent prior).

This is for students currently studying at any accredited institution
I can be contacted directly at president@nswaqua.com.au or by phone on +61 (0)439 468 201 (email should be your first point of call).

Regards
Paul Van der Werf
President

Event Description
We will be covering a range of topics suitable to anyone wanting to learn more about designing and operating recirculating aquaculture or aquaponic systems of any size over the intense two day short course presented by Dr Tom Losordo and Dr Wilson Lennard.

Some of the topics that will be covered during this workshop (Full list of topics to be confirmed):

System design and management

Aeration
Plumbing
Components
Construction Techniques
Operation

Fish production

Stocking
Feeding, growth and survival
Harvesting and processing
Water quality

Plant Production

Seedling production
Importance of pest identification
Disease and insect control
Nutrient dynamics

Economics and Marketing

Aquaponics economics
Effect of scale vs Available market
Marketing Fish
Marketing Plants

About the Presenters:

Dr. Tom Losordo is the Director of Aquaculture Systems Engineering for Pentair Aquatic Eco-Systems. Dr. Losordo has a Bachelor degree in Biology and an M.S. and Ph.D. in Biological and Agricultural Engineering. Having been involved in aquaculture for more than 38 years, Dr. Losordo recently retired as head of a program of applied research and extension at North Carolina State University in the area of recirculating aquaculture production systems.

Dr. Wilson Lennard is the Director of Aquaponic Solutions and has been studying aquaponics for the past 10 years. He is a PhD graduate from Australia (RMIT University, 2006) with practical commercial aquaponics experience and knowledge. Wilson also has scientific and engineering skills and experience in associated aquatic disciplines, including freshwater aquaculture, marine aquaculture, hydroponics, integrated aquatic farming systems, freshwater aquatic ecology and environmental biology. These skills and experience have been accumulated over a professional scientific career of almost 20 years.

Venue and cost

The venue will be the Soldiers Point Bowls Club, 118 Soldiers Point Rd, Soldiers Point NSW 2317 We are arranging for discounted accommodation rates which are located next to and across the road from the club (walking distance). So hold off on booking your accommodation.

Date: 21 September 2013.

The Elasmobranch Husbandry Manual is a single-reference guide detailing the hands-on care of elasmobranchs; a “how to care for” sharks, rays and chimaeras. This volume is intended to assist in the development of new exhibits, aid in the training of husbandry personnel, prepare scientists for hands-on work with elasmobranchs, and answer specific questions about this important taxonomic group. The entire Elasmobranch Husbandry Manual is available to download free of charge from this site https://sites.google.com/site/elasmobranchhusbandry/manual

Last night, we had over 80 registrants attend the webinar on diseases in ornamental fishes. It took a unique approach, working from the fish species and then delving into the common issues they get.

Dr Loh has been invited to present more of these entertaining and informative talks for the World Aquatic Veterinary Medical Association.

Do you think dolphins are over-rated? Are you in love with sharks?

This group is dedicated to the conservation and ethical care of sharks, skates, rays and chimeras.

Check out information on the up coming conference which will be held from 11-13 November 2013 in Monterey, California, USA. http://www.elasmobranchhusbandry.org/

With the national veterinary registration in full swing in the states of Victoria, Tasmania and NSW, and with my primary registration in WA, you can now access The Fish Vet’s services in most parts of Australia. With modern technology on hand, you are no longer restricted to using fish vets located in the eastern states. You can now access the vet from the west.

Does this mean that you can get scripts for veterinary medicines or get drugs sent in the mail every time you need some Flagyl, Baytril or other antibiotics for your fishes?

Under the veterinary regulations,
a valid veterinarian-client-patient relationship (VCPR) is necessary. What does this mean for your situation? It means that I must have personally seen your fish and/or visited your premises at least once in the past year before I can give a written veterinary prescription or order, for distributing and/or administrating medicines and, aquatic disease vaccines and bacterins.

A great way of utilising Dr Loh’s services if you are in remote locations include histology slide processing and histopathology assessments.

 

In most fish, faecal trails do not hang on for a long time since their normal swimming action would break the trail. Goldfish tend to have a longer trail because they swim slowly and their trail is of larger diameter, making it ‘tougher’ to break. But these should come off easily when the fish is disturbed.

 

Healthy faeces should be dark and not contain gas bubbles. If it contains bubbles, causing the faecal trail to float (see picture below), then there might be issues. Bacterial imbalance or parasites may be possible reasons. The way to investigate it is to examine the faeces under the microscope to look for evidence of parasites and to culture the gut flora to check for presence of pathogenic bacteria. Over feeding is obvious when the faeces produced is the same colour as the food you fed them.