Internal Parasites: Need Help

I believe I have an internal parasite problem. It’s been taking out my guppy one by one. They begin to swim lethargically at the top, stop eating and then die.

Long agonizing story short, I did some full tank medications, fed medicated food and still... the parasites remain. I have a 45 gallon Eco Complete substrate 3 and a half inches deep. HOB filter, sponge filter, fully planted, fire red cherry shrimp, sakura, salt and pepper corys, otto cata, shrimp and some snails.

My question is, can I remove all the guppies without removing the scavenger fish, the. Let the tank sit for 4 weeks, and will this kill off the remaining parasites in my tank?

Thanks in advance.

I’m at the point where I am seriously contemplating breaking the tank down because this is the first time I’ e dealt with internal parasites and it seems hopeless.

 

They begin to swim lethargically at the top, stop eating and then die.

It could be an endoparasite, but I think it's important to note that these are nonspecific clinical signs and can be associated with bacterial, viral, parasitical, fungal pathogens as well as other agents (genetics, environment, etc.).

Were there any other signs/symptoms that you can note? What medications have you used so far?

My question is, can I remove all the guppies without removing the scavenger fish, the. Let the tank sit for 4 weeks, and will this kill off the remaining parasites in my tank?

Without more information, it's impossible to say. Some endoparasites form spores and can survive quite a long while: for e.g. Pleistophora hyphessobryconis ("neon tetra disease"), one of many microsporidians, can survive for over a year in tanks.

 

Is there a medication(s) that can eradicate what you described without having to remove the shrimp?

 

Is there a medication(s) that can eradicate what you described without having to remove the shrimp?

P. hyphessbryconis was just an example. There is insufficient information as to whether your guppies had a microsporidian infection.

In any case, there is no drug treatment for microsporidian infection recommended in the clinical literature due to the lack of clinical testing. The suggested treatment for microsporidian infection is quarantine and disinfection (typically with chlorine).

 

Symptons are the lethargic swimming/wobbling in place at the surface with flat dorsals and clamped/pinched tail fin , white poop, total disinterest in food, emaciation then death. Just today 2 of the more healthy fry in the tank began to spiral swim (which was a first for me) I euthanized them.

Several weeks back I API Cure dosed the entire 45 gallon tank. I used API cure medicated food treatment next, then tried dosing Paraguard and am on the 4th day. I took the 7 fry that were showing the tell tales signs of severe starvation with zero interest in any kind of food

 

Following as I’m dealing with this right now with my guppies. Several doses of general cure didn’t help. I’m doing prazipro right now and I lost a couple during the treatment however one of the emaciated one seems to be gaining weight. I’ll do one more treatment then observe.

 

Symptons are the lethargic swimming/wobbling in place at the surface with flat dorsals and clamped/pinched tail fin , white poop, total disinterest in food, emaciation then death. Just today 2 of the more healthy fry in the tank began to spiral swim (which was a first for me) I euthanized them.

It is difficult to interpret (and note that I'm not a fish veterinarian) what the underlying condition may be as none of these grossly visible clinical signs are pathognomonic. That is, none of them are exclusively characteristic of one particular disease (or a family of pathogens) such that it's an "aha!" moment.

In practice, I find that there are two approaches:

(1) Treating possible pathogens systematically with a series of medications. This is somewhat problematic as we often have limited useful clinical data with which we can form a treatment plan. We typically have to start from a "hunch" and work our way from there.

It's also not a "stress free" approach as presumptive use of medications can be harmful: it can lead to immunosuppression, iatrogenic secondary infections and it can make recovery more difficult (if not impossible). There is also limited guarantee of successful treatment.

That being said, API General Cure has metronidazole and praziquantel as its active ingredients: metronidazole is mainly effective against diplomonad flagellate infections ("hexamitosis") and praziquantel against cestodes (tapeworms). It may be worth treating with an anthelminthic (dewormer), such as levamisole, to rule out a nematode (roundworm) infection.

If that is unsuccessful, it may be worth treating with Terramycin (oxytetracycline) or Maracyn 2 (minocycline) as the antibacterial spectrum of activity for both antibiotics is mainly against Gram-negative aerobes, which represent most of the bacterial pathogens of fish. If that is unsuccessful, then a Gram-positive antibacterial, such as Maracyn 1 (erythromycin) may be used.

(2) As you mentioned, stripping down the tank and disinfection is a more assured way of inhibiting the transmission of an unknown pathogen. This post of mine in another thread contains useful information on disinfection.

 

Awesome detailed information my friend, thank you!

My main concern for the future is due to the fact I have a few ThaI guppy strains and the fear is the fry and juvies will just keep contracting whatever it is from now on. This will defeat the purpose of my hobby, which was a calming time for me to reflect and recharge from a busy life.

Another quick question, before I attempt to zap the main tank, the shrimp would need to come out correct?

 

Another quick question, before I attempt to zap the main tank, the shrimp would need to come out correct?

Correct. My strategy with disinfection is a fairly thorough strip down: plants, decor, substrate, livestock, etc. But this may not be viable in all cases, especially with very large tanks. With planted tanks, the disinfection process can also be more challenging: many (if not all) plants are very unlikely to survive through a 30 minute soak in 0.25% bleach, and a 20-60 second dip in 0.25% bleach may not be sufficient to ensure adequate disinfection.

It's worthwhile to remember that disinfection does not equal sterilisation, and that the purpose of disinfection is to minimise (not eliminate) the likelihood of a pathogen being transmitted. In practice, it's a risk versus trade-off scenario that we all have to evaluate based on our risk tolerance.