Worm identification

[meadoughlark]

Hi all,

I have a 10 gallon tank containing 6 zebra danios, 1 bronze corydoras and live plants (store bought). After 4 months of no issues, I came home 2 days ago to find 1 zebra danio dead and another swimming awkwardly on its back which died a few hours later. I am ashamed to admit that I bought my tank and fish on a bit of a whim without doing much research so have been doing monthly full water changes and complete tank cleans rather than regular partial water changes. Since I was due for one of these monthly cleans anyway and assuming the fish had died due to poor water quality, I emptied the tank, cleaned the gravel, glass and plants, refilled and put the fish back in. (After now reading too late about tank cycling etc, I feel awful writing this).

2 days later I've come home to find the water teaming with tiny white wriggly worms which I'm unable to photograph, but they look a lot like this which I found online:

Some are crawling along the glass as pictured, most are free swimming in the water (both look like the same type though). They range from a few mm to a couple of cm in length. They seem more like detritus worms than planaria to me due to their long, threadlike shape and lack of triangular head, but most websites seem to describe detritus worms as swimming rather than crawling on the glass - do they do both?

The most alarming thing is what I've photographed below, which seems to either be a mass of worms threading off into the water or one large worm clumped together. You can also see a few of the worms on the glass underneath.

Below is a photo of what I previously thought were snail eggs (there are a few water snails in the tank which I assume came in with the plants), but I now wonder if these become the 'worm mass' seen in the previous photo - pure speculation though. I have seen these before the deep clean both above and below the water surface, but never the worms until now. What baffles me is that these have appeared so quickly after the deep clean.

No fish or plants have been added and the gravel and glass were thoroughly cleaned, so where could these worms have come from? Could they have been hiding in the plant roots or the ornate rock I have in the tank?

I'm not sure if these worms killed the fish (I've read that parasitic worms don't swim in the water), I'm just worried that they could cause a problem to the remaining fish. Although my common sense tells me an aquatic worm is not adapted to survive in the human digestive tract, I'm also a little worried that I could have been infected with these things during cleaning. I live in the tropics in Thailand so these could be different from the planaria and detritus worms that seem to be common in US and European aquariums?

Sorry for the long post, I hope someone can put my mind at rest.

 

[Colin_T]

Hi and welcome to the forum

They are not planaria so are most likely a species of detritus worms. They occur all over the world and live in the gravel around plant roots and under objects resting on the substrate. They normally stay in the gravel and only come out and swim around when there is something wrong with the water. Poor water quality, ammonia, nitrite or high nitrate levels can cause the worms to leave the gravel and try to escape. Medications, salt & chemicals added to the water will also cause them to try and escape. However, they don't live out of water so usually crawl up the glass in an attempt to get out of the tank.

It is unlikely the worms killed the fish, but they are a sign the water is not suitable for them. This would also explain the fish dying.

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Reduce the feeding to once every second day and only give the fish a small amount of food. They should eat it all within 20-30 seconds. Remove any food that is not eaten within a couple of minutes, or that sinks to the bottom.

I would also do a 75% water change each day for the next week. Then do a 50-75% water change each week after that.
If you are using tap water, make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Use a gravel cleaner (like the one in the following link) to clean the substrate each time you do a water change. You can leave the fish and plants in the tank when you do this. Just use the gravel cleaner to syphon water out of the tank into a bucket, and while water is syphoning out you push the gravel cleaner tube into the substrate and lift it up. The gunk in the gravel gets drawn up and out with the water, and the clean gravel sinks back to the bottom.
http://www.about-goldfish.com/aquarium-cleaning.html

When you clean the filter, wash or squeeze out the filter materials in a bucket of tank water. After that clean them again in a second bucket of tank water. Then put the filter materials in the tank and wash the filter case and motor under some tap water. When the motor and case are clean, put the materials back in and fill the filter up with tank water, then turn the filter back on.
Filters should be cleaned at least once a month, even if they look clean.

If you don't already have any buckets specifically for your fish, then buy a couple and use a permanent marker to write "FISH ONLY" on the buckets. Then use those buckets for the fish and nothing else. And don't let anyone else use the fish buckets for anything else.

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Planaria and detritus worms do not affect people but there are other bacteria & parasites that can. Generally these organisms can only infect people or animals if you have open wounds on your skin and contaminated water gets onto the wounds. Or if you drink the contaminated water.

Washing your hands and arms with warm soapy water after working in the tank will remove anything on them. And if you have any cuts, scratches, sores, open wounds, then keep out of the aquarium until the sores have healed. Alternatively wear a pair of rubber gloves so the water can't come in contact with your skin.

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If any more fish look funny or die, take a picture or short video and post it here so we can have a look at it. Sometimes the photo can provide information about why the fish died.

 

[IHaveADogToo]

+1 on detritus worms.

have been doing monthly full water changes and complete tank cleans rather than regular partial water changes.

And that's why you have an infestation.

You're not going to get "rid" of these worms. You can reduce their population with routine gravel cleanings and water changes, though. Once a month is not frequent enough for water changes. Even if you're changing all of the water, you're still going far too long in between changes. These worms live in the substrate of lots of aquariums but are usually never seen, and are actually beneficial for breaking down waste. There can be thousands of them in a tank but you never see them if the tank is healthy because they stay in the substrate. They only occupy the water column when there's a problem with the water; basically they're trying to get above whatever is in the water they don't like, usually a toxin like ammonia or nitrite.