https://www.reef2reef.com/threads/fish-and-treatment-guidelines-with-chart.283450/ Try this. I only ever owned 2 gobie types excluding freshwater types. From what I understand they can be sensitive, and need to ramp up slower. I can't say for certain.
@Jay Hemdal I see you comment in this thread how do you feel about chart.
That chart is problematic for me - I divide copper products into three different categories - ionic (copper/citric acid) amine-based (coppersafe and copper power), and then Cupramine.
I do not think
anyone has the experience to make such a detailed chart. Nobody I know mixes up their copper treatments and then brings in so many different species so as to get good data like that. That means people have relied on external information, and that is always an issue. Two common cases that I see: 1) somebody uses a reducing agent while dosing cupramine and the fish die, and they report "copper sensitivity". 2) somebody slowly ramps up copper in response to a protozoan disease and the fish dies - and they conclude it died from copper toxicity, when it actually died from the disease because full copper wasn't attained soon enough.
All of this "ramp copper up slowly" stems from the use of copper sulfate/citric acid solutions back in the day (it is still sold in Europe). It was tricky to dose, and you needed to take 48 hours to get to a full dose with care not to overdose. From this, people over-extrapolated that to other copper medications. I routinely move fish into full coppersafe, I've been doing that since 1980, and I've
never had any issues. I do NOT have much experience with Cupramine, and rather than rely on reports from others, I tend to play it safe and either not recommend it, or suggest a 48 hour ramp up time with it.
As far as the original question? Well, I HATE engineer gobies and won't buy them (grin). I have dosed them with Coppersafe back in the 1980's and don't recall any particular issues, but your mileage may vary. One big issue with these - although they are a pretty hardy species, their low value and cryptic habits make them a prime candidate for being collected with cyanide.
As a side note - I dimly recall that these are active mimic of the venomous coral catfish....
Jay