Figure 8 Developed Lump on the Side of Jaw

[Colin_T]

What would the normal protocol for a lump of this nature?

Keep the tank clean and wait and see what happens with the lump.

 

[Martin6562]

Dear Colin,
Thank you for getting back so promptly. We'll wait it out then. Just so all parameters are shared. This is 125 litre tank with just two F8s in. It has a large external filter capable of filtering a tank 4 times the size. The water temp is automatically regulated to within 0.3 degrees Celsius; I complete an SG test every day using a refractometer; and monitor the water quality with respect to NO3, NO2 and NH4 and the more dangerous NH3 at least once a week. The PH is automatically adjusted within ph 0.05 using a sophisticated CO2 injection system. I complete a 50% water change once every couple of week ensuring the water, filtered for nitrates and heavy metals, is only added to the tank when it meets an identical SG and temp . I feed the F8s every other day.
Kindest regards,
Martin.

 

[ChefAlex]

Dear ChefAlex,

Many thanks for this. I am aware of water SG values, hence my concern. As you will know F8 naturally live in brackish water and whilst they can live in non-brackish conditions they thrive and live longer in the former. I regularly feed my F8 a range of shell foods including snails from a colony I grow for them, whole shrimps in their shells, crushed mussels in their shells etc. He does seem perfectly happy and has definitely not lost his appetite. What would the normal protocol for a lump of this nature? I'm pretty sure bagging him up and taking him to the local tropical vet is not the way forward.
Kindest regards,
Martin.

For the lump just monitor closely, you’ve already tried melafix to no avail which would have been my suggestion.

As for the the puffer, Dichotomyctere ocellatus is purely a freshwater species, it has never been collected in brackish waters in the wild. Icthyologists confirm this species is purely freshwater in several sources including FishBase. The brackish water misnomer arises from their euryhalinity, likely a holdover in their evolutionary timeline. Their lifespan has never been fully documented in aquaria using any reliable quantitative methods, so their increased lifespan is brackish water is likely untrue. I kept a specimen in a freshwater, neutral pH tank for over 10 years. There was a knowledgeable member here on these forums about 15 years or so, Neale Monks, who was very informative on brackish water species. He has a book or two published on brackish water aquaria if you’re ever interested.

 

[Martin6562]

Many thank for this. This is very informative. Everything I have read, which I appreciate is not extensive, refers to F8's natural habitat as being brackish. Evidently this is not the case. I wasn't aware of the term euryhalinity. Really interesting. Perhaps I will then slowly decrease the salinity of the tank? I will check out Neale Monks texts. Huge thanks for sharing your extensive knowledge with me. I will let you know how my F8 progresses. Best wishes, Martin.

 

[ChefAlex]

Many thank for this. This is very informative. Everything I have read, which I appreciate is not extensive, refers to F8's natural habitat as being brackish. Evidently this is not the case. I wasn't aware of the term euryhalinity. Really interesting. Perhaps I will then slowly decrease the salinity of the tank? I will check out Neale Monks texts. Huge thanks for sharing your extensive knowledge with me. I will let you know how my F8 progresses. Best wishes, Martin.

There’s really no need to convert to freshwater, unless you really want to, they still do very well in a little salt.

I think the term “lightly brackish” best describes a lot of species we keep in low salinities (up to 1.005) but in fact don’t ever inhabit brackish waters in the wild. For example there are many different species in the bumblebee goby genus Brachygobius. They are all similar in appearance, behavior and difficult to identify for the average hobbyist. B. xanthomelas inhabits purely freshwater, B. doriae inhabits both freshwater and brackish ecosystems. The reason the B. xanthomelas may do well in lightly brackish water aquaria has to do with their penchants for hard, alkaline water and again the timeline of their evolution as allowed for some euryhalinity like their closely related cousins. That combination of
euryhalinity and preference for hard waters is two fold, it’s not to say that species who prefer hard water (African cichlids) would survive in lightly brackish water.

 

[Martin6562]

There’s really no need to convert to freshwater, unless you really want to, they still do very well in a little salt.

I think the term “lightly brackish” best describes a lot of species we keep in low salinities (up to 1.005) but in fact don’t ever inhabit brackish waters in the wild. For example there are many different species in the bumblebee goby genus Brachygobius. They are all similar in appearance, behavior and difficult to identify for the average hobbyist. B. xanthomelas inhabits purely freshwater, B. doriae inhabits both freshwater and brackish ecosystems. The reason the B. xanthomelas may do well in lightly brackish water aquaria has to do with their penchants for hard, alkaline water and again the timeline of their evolution as allowed for some euryhalinity like their closely related cousins. That combination of
euryhalinity and preference for hard waters is two fold, it’s not to say that species who prefer hard water (African cichlids) would survive in lightly brackish water.

Again huge thanks for this. I have to ask, what is your background? I will then maintain the brackish conditions - as mentioned earlier this also has the added benefit of impeding the growth of some bacteria.
Kind regards,
Martin.

 

[ChefAlex]

Again huge thanks for this. I have to ask, what is your background? I will then maintain the brackish conditions - as mentioned earlier this also has the added benefit of impeding the growth of some bacteria.
Kind regards,
Martin.

I am a home hobbyist, have had fresh and saltwater tanks since the early 90’s. I am an executive chef professionally, but have a rather keen interest in the science that happens in our home aquariums.