It's a good sign that they were feeding. Time will tell. If the HSB were stressed in transport and crowded together, I've seen them look fine one day and 2 weeks later lots were dying because they had their slime coat scraped off and couldn't replace it fast enough. They fungused up and slowly died.
Time will tell. Optimal Fish Food has a micronutrient pack that helps fish get over periods of stress, so that is another plus for you.
