Can guppy grass cause intestinal blockage?

[kevincanada]

Recently did a plant trim and decided to feed the guppy grass to the koi. Ive since lost three big ones due to some sort of constipation and I'm wondering if it's the plant. All of the small sized koi seem fine. Water is all good ph 7.5. No ammonia, nitrite , nitrate etc. And I've had the fish for years. Any ideas or experience with the plant?

Thanks

Kevin 

[Guppysnail]

I’m sorry you lost your fish. I have never heard of guppy grass causing blockages but I have never owned koi. Could the guppy tank maybe have a disease that transferred? 
 

Ill tag some folks with more knowledge 

@Colu @Odd Duck

[kevincanada]

On 5/22/2023 at 9:23 PM, Guppysnail said:

I’m sorry you lost your fish. I have never heard of guppy grass causing blockages but I have never owned koi. Could the guppy tank maybe have a disease that transferred? 
 

Ill tag some folks with more knowledge 

@Colu @Odd Duck

No I don't think so. Pretty biosecure here. Quarantine minimum 2 months and the guppy grass is the only new thing they've been exposed to. They have had lots of duckweed no problems but this was first guppy grass.

[Torrey]

On 5/20/2023 at 1:16 PM, kevincanada said:

Recently did a plant trim and decided to feed the guppy grass to the koi. Ive since lost three big ones due to some sort of constipation and I'm wondering if it's the plant. All of the small sized koi seem fine. Water is all good ph 7.5. No ammonia, nitrite , nitrate etc. And I've had the fish for years. Any ideas or experience with the plant?

Thanks

Kevin 

Any chance some guppies hid in the guppy grass?

They are sneaky little buggers, and move between tanks a lot easier than I thought possible (or would like to admit). I just got 2 baby guppies in with a shipment of shrimp, and the seller is pretty adamant that "couldn't have happened" but the babies absolutely were in the bag and even easier to see during drip acclimation.

I used to breed cichlids, and used culled guppies and mollies as feeders. I had more than one remove itself from the gene pool by getting a guppy lodged (a desirable effect for me as a breeder, as it is almost always due to a genetic issue in cichlids).

I've never heard of koi having similar issues, because the commercial breeders in Japan practice strong eugenics. Doesn't mean that koi are immune to the problem, though. Just because they are a tough fish doesn't mean impervious.

[kevincanada]

I have been feeding guppy culls for 5 years to these guys and they never had issues. They are almost 2 ft long and ate the guppies like tic tacs so I don't think that's the issue.

[Colu]

What exactly are the symptoms how long between the start of symptoms till they die  are these fish kept in an out door pond or indoors and have you treated with any medication if so did you notice any improvement @kevincanada

[Odd Duck]

I’ve not grown guppy grass myself so I don’t know how tough it is, but linear stuff could potentially act as a linear foreign body which is one of the most dangerous type of foreign bodies.  If they happened to eat long strings of guppy grass it could cause an issue.  Did you attempt to open any of the fish to take a look at their internals?  Did you keep any of the remains that you could open and PM me some pics of their insides?