Wow, Nice topic and it sucks that I missed out. Hope your Hippo is doing better.
In terms of ich, you also have to understand that there are stages of ich. Sometimes you'd see a lot of ich on the fish sometimes around six pm and onwards, then the next morning there aren't much. It doesn't mean it is safe.
You know these ich start out like these eggs or something (I am making terminologies up, sorry), then they hatch and fly around your tank. Then if they find a host, they will attach to it. Usually fish. Then they will burrow inside the fish....skin, fins, gills, anytwhere, eyes, anywhere.
Then they start feeding and sucking the nutrients off of your fish. Then they start growing and they they're visible, like white sugar or salt. There are different forms. There are some that makes your fish look covered with fine salt, there are forms that look like white pimples. Then there are some that you don't even see.
But trust me, they are killing your fish and starving them of nutrients.
Raising the temp just makes the cycle go faster. But it doesn't eradicate the ich.
Raising the sg
will only stress out your fish. And there aren't credible tests that really show effectiveness of hypersalinity.
What I did was raise the temp, and lower my SG
to around 1.080 from 1.024 in three days. You then wait until the ich almost doesn't show any sign on your fish. Usually in two weeks it will disappear. Then you start counting three weeks. Don't add any other fish at that point. Do decent water changes.
After about 3-4 weeks, if it doesn't show any sign, there might be a possibility that you eradicated the ich.
Hyposalinity is not always guaranteed and there are as much rish there in killing a fish out of stress.
Bringing your salinity back must be way slower than how you lowered your salinity. Ich sucks.
But I was successful at saving my blue hippo. I also fed it really tiny chopped garlic. I would only feed them garlic for a week. Usually every other day. In that way they are so hungry that they would eat the garlic even if the taste sucks for them. This is just to boost the immune system, not necessarily helpful to ich. It will help prevent any further parasitic or bacterial infection that may happen during the stressful hypo treatment.
I really do hope your hippo survived it. But you have to eradicate the ich from your tank.