Synodontis secreting a slime on the heater

[Melisa]

I have just purchased a tank that has 3 synodontis catfish in it. They have started cruising over the heater like they are looking for food. At first it looked like they thought it was hot. But now not. There is a white film appearing on the heater where they are cruising. Anyone know why and if this is harmful to the heater? If I need to stop this behavior, how?

Thanks!

 

[Andy Sager]

A picture of this would be more helpful but for now, did you clean the outside of the heater after you moved and refilled the tank?

 

[Melisa]

Picture

I have attached a picture. Let me know if this is not the right way to do this

 

[Melisa]

We moved the tank. The heater did not have this residue on it. I was not attached to the wall at that time. I didn't clean it since I am not sure about using cleaning products on the tank. I bought the suction cup and attached the heater to the wall. It was more recently sideways but I put is straight up to see if they would stop sliming it. I have also noticed that this white in spots are in a few places on the tank but in dots and not to the degree that the is on the heater...

 

[Andy Sager]

That actually looks like it's inside the tube, not outside. Take your finger ( on a clean hand or with a glove ) and see if it wipes off or if it has a feel to it. In some of the old cheaper heaters, the insides tended to decay from use and would create a dust inside the test tube which would burn onto the inside of the tube. I see something white at the top of your heater that may be inside which could explain this. Also, in your picture, just above where the heater cord cuts off, there appears to be a field of white things floating(?). What is that?

 

[Melisa]

Thanks for taking the time to reply.
No, it's not fungus.

We have watched the synodontis put it on there and they have also put a few dots on the tank wall.

Could it have something to do with them eating the Amano Shrimp? When we bought the tank, the owner thought there were 30 Amano shrimp. We only counted 8. Then after the 3 Synondontis acclimated to the new environment, they started eating 1 shrimp a day. We removed the shrimp after we decided the Synodontis were killing them and they didn't die naturally. The Synodontis were very active for those 2 days they were eating the shrimp and the day after while they were still looking for the Amanos. I have never had these Synodontis before and had read nothing about them killing Amano Shrimp.

Today the Synodontis are not very active. They refuse to eat all the different kinds of bottom feeder pellets I have put into the tank. I have tried 3 different kinds including bug bites and API. I will get them some frozen blood worms and see if that does anything. But they were bullying the Corrys I put in there and I need a pleco to get the algea no one else is getting and take care of the bottom better. The Corys kinda stay in a corner so they are not doing a great job on the bottom...

 

[Andy Sager]

Thanks for taking the time to reply.
No, it's not fungus.

We have watched the synodontis put it on there and they have also put a few dots on the tank wall.

Could it have something to do with them eating the Amano Shrimp? When we bought the tank, the owner thought there were 30 Amano shrimp. We only counted 8. Then after the 3 Synondontis acclimated to the new environment, they started eating 1 shrimp a day. We removed the shrimp after we decided the Synodontis were killing them and they didn't die naturally. The Synodontis were very active for those 2 days they were eating the shrimp and the day after while they were still looking for the Amanos. I have never had these Synodontis before and had read nothing about them killing Amano Shrimp.

Today the Synodontis are not very active. They refuse to eat all the different kinds of bottom feeder pellets I have put into the tank. I have tried 3 different kinds including bug bites and API. I will get them some frozen blood worms and see if that does anything. But they were bullying the Corrys I put in there and I need a pleco to get the algea no one else is getting and take care of the bottom better. The Corys kinda stay in a corner so they are not doing a great job on the bottom...

If the cats were eating the shrimp, get frozen prawns ( shrimp) instead of bloodworms. They SHOULD eat those.

I haven't seen this behavior before but I found this regarding synodontis secretions:
"Non-Mammalian Hormone-Behavior Systems
N. Stacey, P. Sorensen, in Hormones, Brain and Behavior (Second Edition), 2009

2.18.5.3.2 Other siluriforms
Although no catfish other than Clarias have been studied in detail, there is evidence for hormonal pheromones in additional families from both the Old and New World. The genus Synodontis (family Mochokidae) is large (>100 species) and widely distributed in Africa. Having found by EOG testing that Synodontis detect steroids, we speculated that, if there were selection for species-specific hormonal pheromones in these catfish, patterns of detection should be most divergent among sympatric species, where selection for specificity would occur. EOG screening of more than a dozen species of Synodontis suggests steroidal pheromones might be ubiquitous in this taxon, since all tested species detect unconjugated 5β,3α-androstan and 5β,3α-pregnan steroids (Narayanan and Stacey, 2003). Although there were no evident species differences in detection of 5β,3α-androstan steroids (all species were most sensitive to etiocholanolone), there were marked differences in detection of the 5β,3α-pregnan steroids. However, because mochokids from the central African Zaire River region all detected a common suite of 5β,3α-pregnans that was different from the suite detected by species from the north and east (Lake Nyassa), it appears that differences in detection of 5β,3α-pregnan steroids result not from selection for species specificity, but from historical dispersal and divergence.

EOG screening also provides evidence for steroidal pheromones in two catfish families from South America, Pimelodidae (Pimelodus pictus and Pseudoplatystoma corruscans) and Loricariidae (Hypostomus sp.) (N Stacey, unpublished results). Intriguingly, these New World species are similar to the African mochokids, but different from Clarias, in that the only steroids they appear to detect are unconjugated. All tested mochokids, pimelodids, and loricariids also detected PGFs (unpublished results), but there is no mention in the literature whether PGFs are detected by Clarias. Given that siluriforms are diverse (over 2800 species in 35 families), globally distributed, primarily freshwater, and hardy, we hope they receive more attention in future pheromone research. "


Based on this, it may be that the secretions are being "cooked" when they touch the heater when it's on. Much like the whites of eggs are clear when the egg is placed in the pan, it's white when it gets cooked. The catfish may be using this to court a female or a female trying to attract a male to her willingness to spawn.

The key is that it does not appear to be any harm to the other fish in the tank so the secretions are not toxic. Unless you see them leaving these white streaks on things other than the heater tube, I have no other explanation as to their color. One thing to keep in mind is that whenever there is a large water change, that encourages many fish species to spawn. Since this happened after the move and I assume you didn't bring all the water from the tank when you moved it, this is another probable possibility.

 

[Melisa]

I see frozen Brine and frozen Mysis. Thoughts on either of these 2 or on brands?

There is a Vampire shrimp still in there but it's about the same size as the Synodontis, so I am thinking it's safe?

I think you are on to something here. There are 3 Synodontis and it seemed that they were chasing 1 away and the other 2 stayed together. It also seemed that the other was nudging the one it was with while they were swimming. I don't have any cyclids in the tank so I don't think they would successfully breed.
But the white streaks are on the surface of the tank also, more on the back than on the front. Now all 3 seem to be hanging together again in the hollow trunk again.

 

[Andy Sager]

I see frozen Brine and frozen Mysis. Thoughts on either of these 2 or on brands?

There is a Vampire shrimp still in there but it's about the same size as the Synodontis, so I am thinking it's safe?

I think you are on to something here. There are 3 Synodontis and it seemed that they were chasing 1 away and the other 2 stayed together. It also seemed that the other was nudging the one it was with while they were swimming. I don't have any cyclids in the tank so I don't think they would successfully breed.
But the white streaks are on the surface of the tank also, more on the back than on the front. Now all 3 seem to be hanging together again in the hollow trunk again.

Ocean nutrition used to put out frozen prawn but I don't see it online. The next best thing would by the mysis shrimp, not brine shrimp. I did see some marine foods that contain chopped prawns so there's an option. Another option is to go to a bait and tackle store and get frozen bait shrimp ( or 1 or 2 live ones for now) and chop that into bite sized pieces. ( Cheaper than using shrimp from the grocery store. ) Once you get them eating something other than the shrimp from the tank, you can try adding another worm product or pellet. ( BTW, mixing shrimp and catfish is a recipe for disaster as shrimp is one of the best baits for catching them. )

The behavior you said the 3 fish were exhibiting sounds like a pre spawning " dance". If they did spawn, no doubt the other catfish or other critters in the tank probably ate the eggs since neither fish is protecting the spawn now.

 

[Melisa]

I was kinda hoping the blue vampire was safe since I never intended to have 2 tanks and the other tank is only 5 gal and has 6 Amano shrimp in it now... See the pictures below. He is pretty big compared to the catfish.