The Fish Vet's Blog

Swimbladder non-inflation is a big issue with raising larval fish and specifically, in marine fish because of their very small size. This paper illustrates the importance of keeping the water surface clean.

Aquaculture Research
Volume 43, Number 9 (August 2012)
	Promotion of initial swimbladder inflation in Pacific bluefin tuna, Thunnus orientalis(Temminck and Schlegel), larvae
	Authors:	Michio Kurata, Manabu Seoka, Yoshizumi Nakagawa, Yasunori Ishibashi, Hidemi Kumai, Yoshifumi Sawada
	Author Affiliations:	no affiliations available
	Source:	Aquaculture Research, Volume 43, Number 9 (August 2012)
	Page Numbers:	1296 – 1305
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Initial swimbladder inflation (ISI) of Pacific bluefin tuna (PBT), Thunnus orientalis,larvae was studied to increase the survival of cultured larvae. Experiment 1 was conducted to explore promotion and inhibition of ISIunder different water surface conditions; including the use of surface skimmer to remove autogenous surface substances (SS), covering the water surface with liquid-paraffin-layer (LP) and oil film (OF), and a control (non-treatment, NT). Significantly higher inflation frequency was observed in SS(62.2%) than NT(11.9%), LP(2.7%) and OF(3.9%). This indicates that ISIin PBTlarvae can be promoted by removal of surface substances on rearing water which inhibit larval air gulping. Experiment 2 aimed to elucidate proper day of larval age to start skimming for promoting ISIwith four different periods of oil film removal: from 3 to 8 (SF3D), 4 to 8 (SF4D), 5 to 8 (SF5D), 6 to 8 (SF6D) days-post-hatch (dph). Significant improvement in ISIfrequency was observed in SF3D (80.2%) but the frequency was very poor in SF4D, SF5D, and SF6D (17.8–7.5%). This implies the need of oil film removal without missing a narrow window, 1 day of 3 dph, to promote ISIin practical PBTlarviculture.
	Citation:	Michio Kurata, Manabu Seoka, Yoshizumi Nakagawa, Yasunori Ishibashi, Hidemi Kumai, Yoshifumi Sawada . Promotion of initial swimbladder inflation in Pacific bluefin tuna, Thunnus orientalis(Temminck and Schlegel), larvae. Aquaculture Research, Volume 43, Number 9 (August 2012), pp. 1296-1305, <http://ejournals.ebsco.com/direct.asp?ArticleID=4D06AD4FDB656433EF32&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=4D06AD4FDB656433EF32

Anisakiasis can be a real problem when eating raw/uncooked fish such as those served as sashimi. How can you reduce the risk of becoming infected with the worm?

Eating farmed fish rusher than that sourced from the wild will dramatically reduce the risk. Another way is to freeze the fish prior to eating. Freezing of herring in the Netherlands has seen a great decline in human cases of anisakiasis.

Have you noticed your fishes are getting hungrier as the weather warms up? Are you increasing your feeding to satisfy their hunger? Beware that your biofilter will lag behind in terms of their ability to convert dissolved fish wastes to nitrate. It’s not unusual to find high levels of ammonia at this time of the year. So keep an eye on it.

The drug cocktails used to treat sick fish are a common scenario I see, with owners travelling from shop to shop to be recommended one treatment after another.

Some drugs do more harm than good,
some may be directly toxic to fish, some may wreak havoc with your biofilter creating toxic water conditions and some when used incorrectly, can lead to bacterial antibiotic resistance.

Even if the medications themselves do no harm, it eats into valuable time and the disease can spread to others and it can progress beyond recovery.

Previous treatments given may also mask signs of disease and may make it more difficult to diagnose the cause of disease. So it is very important to seek veterinary attention immediately at first signs of disease.

I’ve been asked by a colleague to ask a favour of my “followers/readers”. I hope you can help this student out. I completed the survey in under 4 minutes, provided the YouTube video works for you.

See email pasted below.

Many “Tanks!”

R<><

From: M. Sullivan
Date: Wed, Sep 19, 2012 at 1:47 PM
Subject: Fish owner survey
To: Dr Richmond Loh <thefishvet>

Hi Richmond,

As part of my PhD, I’m looking for fish owners to take part in a short (5 minute) online survey and follow‐up after a month. The study explores how we can better provide information about fish care. Is there any chance you would be interested in taking part and maybe sharing with your contacts? I’d be super grateful!

The survey is online at  https://edu.surveygizmo.com/s3/1012880/fish

Can you please like my fanpage?

http://www.facebook.com/thefishvetdrloh

Thank you kindly.

Check out these critters who’ve been massacring my hibiscus in the backyard. Anyone know a good recipe for these or will they become fish food?

That’s very cruel and I saw it previously on a TV show called “Japanese Mad About Fish”. There are some very sick people out there is all I can say.

This was brought to my attention by, Faheem Noor.

—
Yours sincerely,

Dr Richmond Loh
BSc BVMS MPhil MANZCVS (Aq & Pathol)
The Fish Vet, Perth, Western Australia.
Veterinary Medicine for fish.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383

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What do you get if you cross a hydroponics setup with seahorses?

Hydroponies.