Yoyo Loaches- Predatory Behaviour Observed

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CocaCola

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Hi I set up a tank approximately 7 month ago and everything was going smoothly - I have some dwarf gouramis, a couple of black mollys and three yoyo loaches (with a distinct hierarchy). My tank is all hunky dory, I feed the fish with standard flakes, loach flakes, and occasionally blood worms. All my water stats are fine etc. It's a well planted, 70L freshwater tank - with plenty of hiding places.

A week ago I added 4 leopard danios - all of which were gone within the week. This was pretty bad, as I've never had a fish die. When I lost the first one, two days after I had put them in an interim tank to see any signs of sickness etc etc, I got pretty concerned, as I couldn't find a body. I moved stuff around the tank, checked the filter etc etc. I even lifted up rocks, nothing. Over the course of the week I lost another two - again I found no bodies.

Towards the end of the week I was getting ready to feed the fish. I turned the light on the tank, and I saw the three loaches feeding on the last danio - they were all crowded around it, and in a few seconds it would have been completely gone if I hadn't quickly fished the body out of the tank with a net.

Is this behaviour normal? I don't think it is? They're well feed fish - I don't understand has anyone else seen this behaviour? Should I be worried about my other fish?

Thanks,

CocaCola
 
Although i've never seen or heard of this behaviour before and i cant work it out, i can give you some re-assurance as i wouldn't worry about your other fish, as the loaches, as far as i know, have never done this to any of your fish before. Therefore i highly doubt that they would start possibly attacking, then eating your fish that you currently have! Sorry for your loss of the fish by the way. :rip:
 
Hello Coca cola sorry to hear about your fish loss.

There are Three things for sure about this situation:

1. Yoyo's are unbelievably greedy Loaches and will eat anything sitting about this would include dead fish.

2. Although this has nothing to do with your problem it is an issue, You do not have enough of that species they are very social they thrive in number and suffer if there are to few and they can exert there boisterous nature on other inhabitants in your tank.

3. Again nothing to do with your current issue but a very big issue and that is I am afraid your tank is far to small for 1 Yoyo let alone a reasonable sized group I would recommend you find them a new home asap or get a bigger tank because keeping 3 Yoyo's in a 70 litre tank is in my humble opinion cruel.

So to answer your question Yes I have seen Yoyo's eating dead fish, muscles and Prawns they love them I have not seen Yoyo's attacking and killing fish they are considered a good addition to larger communal tanks but who knows they are being enclosed by such a small tank and they do not have sufficient off there own number so who knows how they will act. I would go as far as to surmise that the danio's were either or both, brought already sick from the supplier or did not deal with the transfer to your tank from the supplier and died, then the Yoyo's took advantage of there greedy nature and consumed the danio's.

There is a bio in the fish species index under cypranids, Just encase you have not done any study on this species there is a link to the fish species index at the bottom of my post just encase you do not know were that is I hope this helps and your problem is resolved swiftly

Regards onebto
 
Eating dead fish is quite normal for yoyo's, killing danios is not.

More likely, your danios died on their own. Did you quarantine them long enough to make sure they were healthy?
 
I had quarantined the Danios for a week - and they had shown no signs of illness.

What size tank should I keep the loaches in? I have a larger (150l) tank - but I thought that 70l would be more than enough room for them - they're less about 5cm long!
 
A week is pointless, most diseases take much longer to develop. I quarantine for at least two months, the only exception is fish that is bred by experienced breeders I personally know -- they get one month. LFS fish is dangerous, it has the potential not just die, but wipe out your entire tank.

B.almorhae grow very quickly and will grow *in most cases* better in a larger tank. Dimensions of the tank matter too, perhaps more than the size, I'd suggest a 4' tank as a minimum (55g, or a lower tank that uses the same base). If you feed them well (frozen food like bloodworms but also some vegetable matter like algae wafers), they may get to 3-4" within 3-4 months.
 
Mikev is correct its the actual shape that matters they need long tanks to stretch there fins they can swim at exceptional speeds yes a smaller tank is okay to grow out when there Juveniles but 70 litres is just to small. Again pointing out what I mentioned about the numbers required.

4ft to start working up to 6ft is best again Mikev is again giving you good advice they do grow quite quick unlike Clown loach so the shorter tanks would last no more than a year 3 off mine i got at about 1 inch a year on and there 4 to 5 inches long.

If your looking for a small loach you would be much better of with dwarf chain Loaches or even zebra loach but again 70 litres is a bit small for an acceptable number of this species.

Please do not think I am having a go at you its not my intention its probably (excuse my assumption if I am wrong) the case that you saw them liked the look of them and the LFS said yeah they will be fine without researching the species before buying and if this is the case please do not feel bad as many of us including myself in the early days have impulse purchased a species of fish.

My concern and my intention is to supply you with some good advice and the well being of the fish in your charge.

Genuinely my kindest regards onebto
 
Agreeing with the above....

Small suitable loaches: yunnanilus, kuhlis and related species, some hillstreams (but the tank must be properly designed). Sids (dwarf loaches) indeed one would want to keep in a large group and this gets you into the 3'-4' tanks.
 
Hello all,
Have observed a similar behavior as Coca-Cola, yoyo is a good community fish, however they are nocturnal, Super active when lights are off, other community fish rest in the dark and are often at the lower part of the tank almost sailing, my yoyo loaches surely takes them to be dead and with their sharp whiskers does damage them, I have even seen sometimes they swim by the side of a slower swimming fish aiming for their eyes. Size of the tank matters mine is a 280 liter however I am still finding ways to get this behavior sorted
 
This is a very old thread, the other members are unlikely to reply, but the last post does add useful information.
 
I have had a group of sids for about 15 years maybe a few more. For most of that time they have lived in a planted 25 gal tank with a few rasboras, now down to 4 (combo of Trigonostigma espei and Trigonostigma heteromorpha).

That said, I have seen a large tank with 50+ sids in it and it was amazing. It belonged to a gent who sold discus, so the tank also held a bunch of them.

They have changed the name of sidthimunkis over the years I have had them but they have always kept the sid part.
 
As TwoTankAmin mentioned taxonomy (!) the following from my profile of this species elsewhere may be of interest.

This species was originally described by W. Klausewitz in 1959 and named Botia sidthimunki, the epithet in honour of Aree Sidthimunk, a researcher at the Thai Ministry of Agriculture, Department of Fisheries. In 2004, Maurice Kottelat removed this species from the genus Botia that contains most of the common aquarium loaches and assigned it to the new genus Yasuhikotakia erected by Nalbant in 2002, along with the similar-looking species Y. nigrolineata.​
During his comprehensive review of all known loach species that has been in progress for more than 30 years, Dr. Kottelat determined that these two species form a very distinct lineage, and with publication of his paper in 2012 he erected the new genus Ambastaia for these two species. The genus name derives from Ambastai, the name of a river in a work by the first-century writer Claudius Ptolemy, a Greco-Roman citizen in Egypt who lived ca. AD 90-ca. AD 168. During our time this river has been identified as being the Mekong in SE Asia, the natural home of this species. Thus, a most appropriate genus name.​
The species was briefly thought to be extinct but is now considered critically endangered in Thailand and is protected; hobby fishes are almost certain to be captive bred, and for years have been spawned with hormone treatments. There is no external sexual characteristics but females are rounder in the body.​
Edit: Should have made it clear that this is for the dwarf chain loach species, that TTA calls "sids," Ambastaia sidthimunki. Since yo-yo loaches got mentioned too later.​
 
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Hello all,
Have observed a similar behavior as Coca-Cola, yoyo is a good community fish, however they are nocturnal, Super active when lights are off, other community fish rest in the dark and are often at the lower part of the tank almost sailing, my yoyo loaches surely takes them to be dead and with their sharp whiskers does damage them, I have even seen sometimes they swim by the side of a slower swimming fish aiming for their eyes. Size of the tank matters mine is a 280 liter however I am still finding ways to get this behavior sorted
Hi! It is an old thread, but this is interesting info! May I ask how many yoyos you have in your group, and what other species they're sharing the tank with, please?
 

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