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FAQs on Insect Larvae as Fish Foods: Bloodworms (Red Midge Larvae)

Related Articles: Foods, Feeding, Aquatic NutritionBasic Fish Nutrition by Pablo Tepoot

Related FAQs: Foods, Feeding and Nutrition Aquarium MaintenanceCulture of FW Food Organisms,

Feeding frozen bloodworms      11/30/13
Hi I spent awhile purusing your sight <site> looking but didn't find anything in depth. I've seen it mentioned time and again that feeding bloodworms frozen or otherwise may not be safe.
<Have been implicated (positively correlated) with some disease issues. I'd feed sparingly if at all. Better dead/frozen, defrosted>
I have quite a few fish including BGK (brown and black),spiny eels of the larger varieties, Ropefish, and Mormyrids of a few different kinds and they all eat them. So it struck some concern with me.
It isn't the only food they eat. I can't fit anything in my freezer with all the krill, prawn, brine and Mysid shrimp, muscles, Rotifer,cyclops.not to mention the pellets and freeze dried Tubifex, meal worms, crickets, fruit flies, and the occasional veggie for my fish that enjoy them. So by no means is it all that they eat, but I have a few guys, mainly my dwarf puffers (eat only snails and blood worms) and my juvenile fire eel who won't eat anything but.
<I'd keep looking, experimenting w/ other foods>
I just was wondering if you could give me a little info on why they are considered not safe, and or the problems that can occur. I just want to do the best I can by these amazing creatures I've committed to caring for.
Thanks for your help. You guys do an amazing service.
<Again; I am not aware of a scientific reference that details the root cause/s of using these sewer fly larvae... Just my observation of years of related instances of illness associated with their use. Do please report back to us should you find credible (not simply anecdotal) account of their use, dis-use. Bob Fenner>

Is this a bloodworm?     4/26/13
I've recently (last few months) started building a freshwater tank - the last one I had was taken down due to moving to FL, and the fish given to a LFS (I haven't gotten any new fish yet).  I was kayaking last week and noticed some *Egeria *type plants*,* and grabbed some to start a planted tank.  I kept them out of the tank until today to make sure there weren't any snail hitchhikers, and today I put them in my tank.  As I was cleaning up and about to throw out some plant debris, I noticed little tiny red worm-like things flailing around in the plant matter on my kitchen counter.
After freaking out a bit, I Google searched to see if I could figure out what they are - they are probably in the tank since I didn't notice them until *after* most of the plants went in the tank.  I'm assuming they are bloodworms, but could you double check my identification?
<Could be a Chironomid... an insect larval stage of some sort>
  I'd hate to have any eventual fish I get subjected to a parasite I pulled out of a river.
Thank you!
<Welcome. There's always a chance of introducing trouble/s w/ such wild collecting... Better to run all new material through a few weeks of isolation/quarantine, before introduction to your main/display system. Bob Fenner>

Angelfish and sinking bloodworms
FW Angelfish Ignoring Sinking Food - 10/04/12

Hello: I have a couple of angelfish and I have frozen bloodworms and daphnia in the freezer. I find when I put either of these in the tank, it sinks fast and the angelfish ignore it waiting for flakes that float on the top. When it sinks will the angelfish look for it on the bottom?? I do not want it to rot at the bottom. Thank you
< Cichlids, like angelfish are pretty smart and will find food if they are hungry. I would recommend that the frozen bloodworms be fed only as a treat. We have had questions/problems concerning internal infections that may be related to over feeding bloodworms to cichlids.-Chuck>

Overfeeding with Bloodworms (Freshwater Aquaria)     5/24/12
Good Evening WWM Crew,
I have what might be a problem, but not entirely sure.
<Let's see.>
Basically, while at my LFS I saw them feeding the tanks live
blood-worms...Lots of them.  Now since they had bare bottom tanks the fish ate at their leisure and the worms crawled along until someone decided it was snack time.  Being the enterprising and benevolent fish owner that I am; I decided to get myself some as well.
<Sure. Some debate about how safe they are (they're collected from pretty swampy habitats often laced with heavy metals) but in themselves they are a useful food and fish enjoy them.>
After straining the water they came in through a coffee filter I proceeded to dump 2 ozs worth of bloodworms into a 20 gallon tank.  Good news, my fish loved them...bad news,  a large population has disappeared into the substrate.  They are all still alive in there and basically my concern/question is this; are these going to be filter feeders that clean out my substrate and provide delicious meals to my fish, or am I about to have an explosion of midge flies in my house?
<Likely the latter if the fish don't catch them first. On the plus side, these are non-biting midges, so more an annoyance than anything else, though some people have mild allergies to the larvae at least.>
Follow up to that questions would be "Do I need to do anything drastic or will this problem work itself out?"
and "If not drastic are there any other types of livestock I should get to make sure this problem does not get out of control?"
<Any catfish or loach will eat these as/when they find them.>
Tank parameters are as follows:
2 Cory Catfish (both are getting a massive amount of eating done with so many worms in the substrate)
1 Pleco
<Both these catfish species will take care of them.>
3 Dwarf Gouramis
3 Neon Tetras
3 Red Eye Tetras
3 Bumble bee Gobies
Lighting is done with a 26w LED (not sure if that matters) Water condition is about as good as possible, no nitrites, low nitrates, mid grade alkalinity and hardness.
Any help you can provide would be most appreciated, and as always thank you.
Clay B
<Your tank is going to be fine. Cheers, Neale.> 

Bloodworms   2/15/11
Hi Crew,
Wow at this point I feel like I am almost family with you guys.
Especially Neale. You may just get an invite for Thanksgiving my friend.
I have another question for you regarding both my 5 gallon tank as well as my cichlids. Tonight I fed my fish and frogs bloodworm as I always do. I had been developing some eczema and allergies recently so it was just business as usual. However 5 minutes after feeding the smaller tank (I get much closer to spot feed the frogs) my skin broke out on my hands, neck, and throat, my eyes swelled completely shut and my throat swelled almost shut. I also recently had the flu and was given Azythromycin for it (which coincidentally has epinephrine) which I took right after feeding the fish which seems to have lessened the reaction. This was the worst it has been. I had been treating the rash with a topical creme but it always came back after the feedings. I looked online and it appears some people have a VERY SEVERE allergy to bloodworms.
<Yes, have heard this as well. HOWEVER, as with anything, be sure not to confuse correlation with causation -- only a doctor can confirm an allergy, and jumping to the wrong conclusion could cause you serious harm. If it wasn't the bloodworms, but something else that happened to be around at the time, then you thinking you've identified your allergy would give you a false sense of security. Talk to your MD.>
So severe that in some cases it can trigger an anaphylactic response requiring a 911 call.
This would explain why (much like peanuts) it took months for my body to build enough of a reaction for it to get this bad and why I hadn't noticed anything. I know how well sought after your site is and how people rely on your advice. Please let your readers know about this very serious condition as it can result in a life threatening reaction even if they get near them enough if they are allergic.
<While your experience is worth noting, it should be put in context. By far the commonest sickness people will get from their fish tanks will be some sort of Salmonella infection, through the combination of warm, wet conditions in the tank and around the hood. For most people, fish are far safer than, say, pet dogs or cats, and far fewer people have allergies of the sort you're reporting compared to allergies to cat hair or dog hair. In short, people who be aware that fishkeeping has risks -- just like anything else in life -- and if they're concerned, they should speak to their health provider for the best advice on what to do.>
On a side note....what the heck do I feed my African dwarf frogs, Betta, and SA cichlids who LOVE them. I am most concerned about the frogs who depend on the worms as their sole food source. Any ideas or should they go back to the pet store for their own safety as I am obviously throwing away my bags for bloodworms.
<I see.>
Are there any reliable substitutes?
<Try black mosquito larvae and glassworms, which are as different to bloodworms as sheep are to cows, even though they all look like "worms" to the layman. You can also use pellet foods for all these fish, combined with finely chopped seafood, particularly tilapia fillet, mussels, and prawns.>
Thanks again guys.

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