Orange Russian tomato plant looks sick

[caval3]

Hello All,

This is my first post, We will see how responsive this community is.
I Leave in Santa Cruz, CA. This is my second year planting a lot of heirloom tomatoes, that I grew from seeds.
My plants are doing well except one which I believe is a Orange Russian or a Red German Strawberries. It has 3 very large ox heart fruits on the plant already, but the plant looks like it is struggling. The foliage is curled up and looks almost like the plant is about to die. I gave it more water, then less water, nothing seems to change.
All my tomato plants were planted the same way, with a fish head at the bottom of the whole and 7 more ingredients to feed the plant through its life. I had an incredible result last year, harvesting about 60lbs on my 10 plants in a coastal zone.
Has anyone any idea of what I would be doing to this plant?
Thanks
CaroTomato (Caroline)