How to use a microscope

[Spike Cover]

All,

I'm new to Discus but not to fish. I've been a fish geek most of my life but have spent the past 20 years keeping Koi and learning (and teaching) about their health. From looking over the posts on this board, I see that the Discus hobby has many of the same problems that I've seen in Koi, e.g., people trying to treat sick fish w/o knowing what the problem really is. So in an effort to give back a bit for all the information I've found on this board, I thought I'd post a little about how to use a microscope. This is certainly not an exhaustive treatise but is more the essence of it. You'll need to substitute "Discus" for "Koi" and "tank water" for "pond water" in the blurb below, but other than that it should work. BTW this is something that I wrote for the K.O.I. Guide book (a quick reference guide) for Koi Organisation International.

You can just about spend any amount of money for a scope but in the neighborhood of $150 should get you something very decent. If you're a shopper, you can pick up something used for even less.

If you all find this helpful, I can post some info on various parasites, i.e., what they look like, how they move, etc. If this is "old news," I'll just go back to lurking .

Spike

Capture_2crop.jpg

[DJW]

I have an old oil immersion scope that works fine but it would be nice to have one that takes pictures. It can be frustrating sometimes trying to decide which medication to use, and looking under a microscope can solve the mystery.

Microscopic pictures of various parasites are great if you have some. Identification can still be tricky though. For example, there are zillions of critters that have flagella... its not necessarily hexamita.

[Spike Cover]

I somewhat started in the "middle" with this thread. It should really go like this:

• Something looks "off" with the fish (fish farmers call them ADRs, i.e., Ain't Doin' Right).
• From the clinical signs (same as symptoms in humans), a person should then do what's called a Differential Diagnosis (I'll abbreviate that "DD") which is a list of all the things that might be causing the problem based on the signs.
• From the DD, the person then proceeds to what are termed "rule outs" which just means that they try to rule out the possibilities on their list.
• Example, if one of the possibilities of the DD was parasites, they could do a scrape and scope. If they're decent at that process, they would rule out (or confirm) the existence of parasites.

The value of this should be obvious: if your fish don't have parasites, you shouldn't treat them for parasites. If they do have bugs, you should be able to confirm which parasite(s) are present and only treat for those particular ones.

This is somewhat different from what dealers may do, which is to presume their new fish have all common parasites and they treat them accordingly, i.e., they treat for ciliated bugs (Ich, Trichodina, Chilodonella, etc.) then for flukes (skin and gill types). This is harder on the fish but is more practical than scraping and scoping every fish. I think I read on this board that at least one poster recommended shotgun treatments of all incoming fish (this may have been just for wilds... can't remember).

Once a person knows what parasites are normal or traditionally found on Discus, this can be helpful. If they can all be seen at 40x thru your scope, you usually won't need to go to a higher power. If however Discus get costia (ichthyobodo), you'll need to bump up the magnification to 100x. I've never seen hexamita so I'll have to look into that one... my books say it's about the size of costia, i.e., less than about 20 µm. And, it says it's often internal so you'd have to get a feces sample and scope that (rather than a skin or gill scrape).

Another thing is that many of the parasites are diagnosed in large part on the way they move. Flukes look and move kind of like inch worms if they can get a hold otherwise they just extend and contract, while Ich are round, have a horseshoe shaped nucleus and just slowly rotate. I'm guessing that Discus don't get fish lice or anchor worm. If that's correct, we won't have to worry about those, they can be seen w/o a scope anyway.

I'll try to post some pix and maybe some videos or links so that you can see what the bugs look like and how they move. Here are some pix to start.

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Spike

[Jack L]

i think this is a great idea. going by symptoms alone, it really is a guessing game, so we are forced to treated with broad range remedy. what is the minimum quality scope that should be considered?

[DJW]

Amscope makes good scopes. What you need is a "high power" student microscope that goes at least to 400x, which is enough for most diagnostic efforts except the identification of bacteria. For bacteria you need 1000x and special stains. A gram stain kit can help determine which antibiotic is more likely to be effective.

[Spike Cover]

From my personal experience I'd say you want a compound scope, with 40X and 100X minimum resolution. They usually come with at least 3 lenses on a turret so you'll likely get 400X along with it. If you're like me, you can't use that lens very well (I have floaters in my eyes and they reflect in the scope.) It essential to have a light with the scope, LED is good but anything that's built in is okay. Then you need some way to cut the light down so you don't wash out the image. There's a ring with holes under my cheap scope but I also bought a light dimmer that I attach to the light cord and that works well. Next I'd suggest you get at least a mechanical stage adapter. This will let you scan the slides with decent control. BTW, if you're doing a mucus scrape, I've found that along the edge of the cover slip with which you've done the scrape, to be most productive, i.e., that's where you're most likely to find bugs (parasites).

AmScope in Irvine, CA carries tons of new scopes, and some at pretty reasonable prices. Here's one that's like what I have (except I don't have the 1000X capability - that's where you'd use oil immersion to keep the stray light from messing up the image).http://www.amscope.com/student-micro...cal-stage.html It's $140.

People I know say they've found used scopes for under $100 but that takes some looking.

I've used this simple monocular scope for almost 20 years and it's served me well. I've found a LOT of parasites with it.

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Spike

[Spike Cover]

I'm trying to figure out how to post videos as watching the bugs move is really helpful in diagnosing what the darned things are.

Spike

[Spike Cover]

Can some of you tell me what are the common parasites found on Discus?

TIA,
Spike

[Spike Cover]

Amscope makes good scopes. What you need is a "high power" student microscope that goes at least to 400x, which is enough for most diagnostic efforts except the identification of bacteria. For bacteria you need 1000x and special stains. A gram stain kit can help determine which antibiotic is more likely to be effective.

I've found that you can diagnose most (Koi) parasites with 100X. You can actually see motile rods (twitching bacteria) at 400X but you can't tell what they are. You need a lab (or a bunch of stains and grow-out dishes) to determine what the bug is. But that's not nearly as important as what kills it. For that you need sensitivity testing. That's best done by a lab unless this is already "your thing," i.e., you've worked with this sort of stuff before. But I've found that by the time you get sensitivity testing back from a lab, the fish is frequently dead unless you intervened before that! If you suspect bacteria, this is one time I advocate cut-and-try (for the reason I just gave). If what you try isn't having a positive effect in a few days, I'd recommend switching to another antibiotic.

All this said, if you've got a special fish involved or a bunch of fish, you may want to send a swab off to the lab JIC your cut and try doesn't work and you still have time to save the fish.

[Spike Cover]

Does anybody inject antibiotics in Discus? Or has anyone ever heard of this?

Spike

[Spike Cover]

I should have written "treatise" (instead of "tretus"... spelled phonetically) in the first post. But I'm an engineer and everyone know they can spell much of anything (groan). Sorry.

Spike

PS, for some reason the forum won't let me edit the message. Does anyone know why?

[Second Hand Pat]

I should have written "treatise" (instead of "tretus"... spelled phonetically) in the first post. But I'm an engineer and everyone know they can spell much of anything (groan). Sorry.

Spike

PS, for some reason the forum won't let me edit the message. Does anyone know why?

Hi Spike, I fixed your first post. You only have a 12 hour (or so) window to edit a post.
Pat

[Spike Cover]

Pat,

Thanks and thanks for the explanation.

Spike

[rickztahone]

Cool thread Spike. I have personally only used a scope once to diagnose a discus illness. It was flagellates we saw under the scope and I tried to take pictures of it but wasn't very successful. It made the guess work less sketchy though and it was a tool that I knew would be very handy for any person in the hobby. You can sometimes find these on ebay or craiglist for cheap.

[Jack L]

Does anybody inject antibiotics in Discus? Or has anyone ever heard of this?

Spike

i saw it in an old book i have, i think it was adventures with discus.

the Ds i lost 20 years ago, wouldn't have even thought of it probably. the one i lost this round died unexpected from ich and fast, so no time.