Are my Tilapia sick? If so how can I treat them if they're to be human food?

[JeffLetendre]

Hi all,

For a few months now I've been raising 60 Blue Tilapia fingerlings some of which are now 7 to 8" in length. They are currently in a 70g bare bottom aquarium with a canister filter full of bio-balls, a course sponge and a 13 watt UV. Their waste is 'stringy' and trails up to 8" from them before it breaks free. Also they "flash" sometimes, but they are eating well and I've experienced zero fatalities to date. I feed them a mix of fresh greens (lettuces from my grow beds, duckweed and New Life Spectrum cichlid formula sinking pellets.

This is the first time I've kept Tilapia, but based on my aquarium experience and research their symptoms (flashing and stringy ditritus) I'm thinking they may have an internal parasite. Is that a valid assumption?

In an attempt to kill the parasites that I assume they have I've added kosher salt to the water for a few weeks bringing the salinity to brackish levels, but this didn't fix the problem. I've also fed them lettuce soaked in garlic concentrate. I have to be careful as to what I feed them as they are destined for a dinner plate eventually.

The water is now back to zero salinity. They have been showing these symptoms for months, but otherwise seem healthy.

The water parameters are all fine and I do frequent changes (from my Artesian well).

Any advice/feedback would be appreciated.

Thanks!

-Jeff

[Ravnis]

The "flashing" is also a breeding cue I have observed females do just before they are ready to breed. At 7 - 8 inches they should be reaching sexual maturity if not. Long stringy poo is like a trade mark with tilapia and if it is brown and not white or clearish that seems normal from my observation. at 7-8" they are probably close to 3/4 pound in weight. Thats a lot of fish mass for a 70 gallon tank.

Kellenw has more experience with them than me though so maybe he can fill in any details I left out.

[JeffLetendre]

Thanks for the reply Ravnis!

There's 5 or 6 fish that are 7-8", most are 4-6" about 1/3 are only 2-3". Granted this is still a big bioload for a 70g which is why I'm doing frequent H2O changes (~15-20% / day). I have 5 x 275g water totes (like the ones shown here: http://www.youtube.com/watch?v=HeB5eqAS8fo) that I will be splitting the fish up into soon.

For the most part the ditritus has been dark brownish orange (same as the color of the New Life Spectrum food).

As I mentioned this is the first time I've kept Tilapia. I'm happy to hear that the 'stringy' waste is common to the breed, that leads me to believe the fish are in fact healthy.

I've read that they create beds in the substrate for spawning. Right now the aquarium is bare bottom - do they need substrate in order to breed or will they still spawn w/o it?

Thanks again for the reply!

-Jeff

[DaveOponic]

Hi Jeff


I have kept Tilapia for about three years now and sucessfully bred them. (Not difficult) In fact I have only ever purchased 12 Tilapia. I have freshened up the gene pool of the fish with wild fish caught from time to time in local waterways and also some Tilapia from a fishing pond farm.

By the sound of it there's nothing wrong with your fish. I have kept a few Tilapia in aquarium tanks on occasions in order to encourage breeding but it wasn't successful. On one occasion lost three or four fish due to aggressive behaviour as the males tried to establish their pits and fought with the competition.

I think you will have healthier fish if you can give them a bigger environment, say 500 - 1,000 litres or more and get them out of glass. My experience is that they are a shy fish and don't like being observed (most fish I guess are like this) I have found they breed easily in a concrete pond where they have hiding places and lots of moss, algae etc.

I did try putting gravel in the tanks and in the pond. The fish made their "pits" and it was fascinating to observe this territorial behavior. I think that they won't breed if the tank is too crowded. I have had fry appear when there have been up to twenty or so fish in a 1,000 litre tank.

Another tip..... as soon as you see the fry.... and they are tiny and lightning fast ... as soon as you see them in the tank... remove the adult fish. You will never net the fry ... so you could also drain the tank if you are able and separate them that way.

If you don't isolate the fry, most of them will be eaten.

One day I drained my concrete pond as it was getting murky. I had about 20 -25 Tilapia in there of 300 - 700g size. As the last of the water was emptying I noticed hundreds and hundreds of tiny Tilapia floundering on the cement path. So I used a leaf and scooped them up into a foam drink cup.
I managed to save maybe a few hundered and they are now about 4-6 inches long. I took all the adults out of the pond and have been feeding them cruched pellets for the last two months or so.


Dave

Thanks for the reply Ravnis!

There's 5 or 6 fish that are 7-8", most are 4-6" about 1/3 are only 2-3". Granted this is still a big bioload for a 70g which is why I'm doing frequent H2O changes (~15-20% / day). I have 5 x 275g water totes (like the ones shown here: http://www.youtube.com/watch?v=HeB5eqAS8fo) that I will be splitting the fish up into soon.

For the most part the ditritus has been dark brownish orange (same as the color of the New Life Spectrum food).

As I mentioned this is the first time I've kept Tilapia. I'm happy to hear that the 'stringy' waste is common to the breed, that leads me to believe the fish are in fact healthy.

I've read that they create beds in the substrate for spawning. Right now the aquarium is bare bottom - do they need substrate in order to breed or will they still spawn w/o it?

Thanks again for the reply!

-Jeff

[kellenw]

Hi Jeff,
Your tilapia sound fine. Tilapia are "poop machines", and they will often have a long string hanging from them. Flashing is normal behavior. They do it pretty much all the time. If you are wanting them to spawn, a bottom substrate like regular aquarium gravel will encourage your most dominant male or two to "nest up" more readily.

Feeding NLS fish food to tilapia is going to be extremely expensive. You should check out www.premiumfishfood.com. The food is every bit as good as NLS and costs a fraction of the price.

[JeffLetendre]

Thanks for the additional replies, Dave & Kellen!

I ordered (and received today via USPS) a batch of Fry Powder, Crumble, Fingerling Pellet, Intermediate Pellet. Yes, it is much more reasonably priced than NLS food! Solid lead, Kellen!

Of course having mentioned a zero fatality rate thus far, I found one dead Tilapia over the weekend. I suspect/hope it was merely a victim of being bullied by an aggressive male which reaffirms that they need to be split up into the larger tanks.

I plan to get a few 'batches' of fry from these fish before I need to out-breed w/ other Blue Tilapia.

[hellbent]

hi,
i have set up a breeding tank in a 55 gallon i got off of craigslist for $80. i used cherrysnapper's hatchery method of putting in the tank five 5 inch clay pots with some shade cloth tied over part of the opening. i get about 200+ fry a month which the adults do not eat.
they are super shy but at night with the aquarium lights on and its dark outside its nice to see them floating around instead of hiding.

[DaveOponic]

Hi Hellbent,

Can you be more specific about the pots? Are they for the fry to hide in? Is the shade cloth big enough for the fry to pass through but not the adults? Or are the pots for mating?

I have lost quite a few fry as they just get eaten. I haven't purposely tried to breed the fish but always end up with enough to keep up the numbers.

[hellbent]

Hi Hellbent,

Can you be more specific about the pots? Are they for the fry to hide in? Is the shade cloth big enough for the fry to pass through but not the adults? Or are the pots for mating?

I have lost quite a few fry as they just get eaten. I haven't purposely tried to breed the fish but always end up with enough to keep up the numbers.

i am not sure about the measurements of the pots themselves, i think they are 6" clay pots. the shade cloth i have either split like a curtain or just covered 1/2 of the pot opening and tied it down with string. sometimes the shade cloth comes off.
the pots, as i understand it, creates a little cave for the females to lay her eggs, giving them privacy. i have about 9 fish in there, someone was kind enough to give them to me and sexed some of them, but i cant say how many are female in there. the fry just float at the top.
perhaps my tilapias are of a kind temperment. i had a 10th fish in there, but took it out as it was definately eating fry. it was smaller then the others, perhaps younger.
currently i have a 30 gallon and 20 gallon full of fry/fingerlings so i had left this current batch of fry in the tank for a month, with seemingly no loss of fry.
currently the only filtration i use is those foam filters, and change out the water weekly. i do about a 60% water change and i do not dechlorinate first as some do. (hawaii water has some chlorine but not as much as other places). there is a heater in the tank as i have heard that well oxygenated and warm water encourages faster fish growth.
all of this was based on mike sipes' tilapia hatchery manual, but i think he has taken it down since.

[kellenw]

The pots are there to provide some refuge for the female AFTER she has spawned and is holding the eggs in her mouth, not for the females to lay their eggs in. When holding, the females are extremely vulnerable to aggressive tank mates because their best defense (their mouth) is in use. As a result, the females can really take a beating without some place to hide. A pot, some larger pvc pipe, some plastic plants or something similar can all be placed in the tank to provide some cover for the females who are holding eggs.

In short, here's how the spawning process works for maternal mouthbrooding tilapia (Oreochromis spp.).
- Male builds nest. Usually this is by digging a round pit in the substrate about 8 inches wide. Lacking a substrate in the tank, he'll usually just guard a corner in the tank.
- Male then attempts to lure gravid females (females ready to lay) over to his nest. During this time, he will also aggressively defend his nest against intruding males and any females who aren't ready to spawn.
- Once a female "accepts" his invitation to his nest, the pair will swim around the nest nearly side by side, sometimes doing this for several hours, other times just for a few minutes. Some call this the "spawning dance".
- Next, the female begins to lay eggs. She does not lay them all at once, but perhaps maybe 10% at a time. The female will lay some of her eggs, and the male will swim close to her and attempt to fertilize them. Then the female will gather the ones she laid into her mouth, and then repeat the process until she has laid all of her eggs.
- Once egg laying is completed, the female will often (no joke) place her mouth down by the male's vent area, and he will expell a large amount of milt into her mouth. This is particularly common in Niles, but other have been seen doing this as well.
- Now that spawning is complete, the male basically kicks her out and starts looking for the next mate.
- The female retreats to whatever cover she can find and holds the eggs in her mouth for 6-8 days.